Migration and immigration are not a new phenomenon in Europe. From the perspective of European immigration history, the phenomenon of immigration and migration within and beyond Europe has always existed. In particular, the historical process of European integration, which began after the Second World War, has strengthened the number and scale of immigrants crossing the border. Germany, which has always been proud of the German nation, has become more and more colorful in the process of European integration. Especially after the 1950s, within its unified national boundaries, there is a growing number of immigrants with multiple structures and nationalities. They are mainly working immigrants from southern and Eastern Europe (arbeitswanderer), local former guest workers (Gastarbeiter), political asylum seekers (a sylbetrager) and other refugees (fruechlinge) from all over the world. From 1960 to 1990, the number of foreigners living in the former West Germany rose from 681.61 million to 5241.18 million, an increase of 764%, to 6.5 million in December 1992 and 6.8 million in December 1993, an increase of nearly 1000%. About 4million of them, accounting for 62%, came from countries that used to recruit labor. The proportion of foreigners in West Germany rose from 112% in 1960 to 812% in 1990. Since then, there has always been a large group of immigrants in Germany. The reunification of Germany in 1990 did not prevent the United Germany from moving towards an immigrant country. Of the 820000 immigrants in Germany in 1990, only 46.16 million emigrated (+35.14 million). In 1991, 491.72 million emigrated (+42.13 million) out of 920000. In 1992, 981.69 million emigrated, 711.03 million emigrated (+27.16 million). This does not include the high number of "blacks" who are not registered with the Immigration Bureau [1] (p230-231). On the road of European integration, Germany is becoming the central rotating stage of European immigration phenomenon. As Professor Klaus j1bade, an expert on immigration in Germany, said, Germany is increasingly becoming an atypical immigration country [2]. This paper intends to make a preliminary study of the historical process of German immigrants since the end of the 19th century from the perspective of historical genetics, using the theories and methods of sociology and history.

There has always been immigration in Germany. There has never been a period in Germany. As today, all political parties and the public are widely involved in the discussion on the issue of foreign immigration. In the eyes of many Germans today, the social phenomenon and fact that a large number of foreigners exist in Germany, as well as the social collision of the German and foreign immigration movement, are very dangerous new social phenomena. However, from the perspective of historical genetics, we will clearly find that the cross-border immigration movement and the collision of their different national cultures in history and reality are not exceptions in Europe and even the whole world, but the most basic law of human social development. Many people who settled in Germany today, called Germans, are actually descendants of foreign immigrants. Millions of Germans who moved out are also foreigners abroad, just as today's foreigners are in unified Germany. Professor Klaus J1 bade, a famous German scholar of Immigration Studies and professor of the Institute of immigration and Intercultural Studies (IMIS) at O snabrueck University, in his book "cross cultural challenges: people crossing borders and people crossing borders" (die m u ltikurtu relle herausforderung: m enschen Ueber grenzen2 grenzen Ueber m enschen), believes that in the historical memory of Germans, what should be aroused is the historical memory of those "little Germans" and "German regions" with a large number of immigrants. In the 19th century, when crossing the Atlantic Ocean to the "new world", the German generation went abroad, just like today's "little Istanbul" or other immigrant descendants' immigrant areas in a multi-layered German city, or like today's "Turkish city" outside Turkey in Berlin, many big cities in the "new world" of the 19th century were strongly marked with the social mark of "German American" of Germany, not including the Germans in the Midwest. Professor bade believes that the facts of knowledge development and historical changes show that the growth and development of human knowledge and skills are closely related to the migration of people. From the perspective of European history, in the professional reference books, it used to be that his abilities, skills and practical experience knowledge were increased through roaming and migration. This is why in the history of Europe, there were many famous thinkers and scholars who roamed the European countries in order to write books. If so observed, the Germans themselves are also involved in the problem of population migration. Because in history, many Germans abroad and many foreigners in Germany are unique social components. In fact, they have experienced many forms of immigration across the border: emigration, immigration and transit immigration, working immigration from Germany to foreign countries and from foreign countries to Germany, and so on. If we carefully examine this period of German history, we will find that there is not only the migration of people across the border, but also the movement across the border of people. In history, Germany also has strong internal migration across a wide range of regions. We call this internal migration population as work migration, from ruhrpolien to ruhrmasueren, and from Eastern Prussia to the industrialized Ruhr and EM Scher regions of montan. During the Second World War, a large number of refugees and deportees in Germany were relocated to the South or outside Europe. This is the direct consequence of German war policy during World War II [1] (p232). To sum up, the historical experience and social reality of Germany is that since the industrial revolution, there have always been conflicts between the majority and the minority, and between natives and foreigners. This conflict has been complicated by historical recollection, which is also suitable for the opposite social phenomenon of the movement from people crossing national boundaries to people crossing national boundaries. In the history of Germany, the exclusion of minorities, such as Jews, Sinti and Roma, and other minorities in its territory, generally speaking, is not continuous or linear. But what can be clearly identified is that in the early 19th century, the road to draw a clear line with outsiders from the "beautified race - Romans". "Ethnic national (ethnic)" was aimed at immigrants in the late 19th century. Germany, a state socialist country in the early 20th century, was notorious for its genocide against some foreigners and the brutal persecution of immigrants in Europe occupied by Germany. It was not until the Allied and Soviet forces occupied German territory that Germany came out of the shadow of terrorist crimes against ethnic, cultural, regional and other nationalities.