The article presents the reasons for the mass migration of the Kazakhs living in the People's Republic of China to foreign countries in 30`s of twentieth century, including India, Pakistan, Turkey and Europe. The study compares, examines, and correlates different data and the facts in Part IV of the comprehensive study by Chinese scholar Su Beihai General History of the Kazakhs, and the reasons, motivation, circumstances, and fate of the relocation were systematically recorded. Su Beihai saw the nomadic Kazakhs passing through Gansu and Qinghai provinces of China and collected a lot of material about them. Previously, due to strict censorship of the history of minorities in the People's Republic of China, the aforementioned four-volume book by Su Beihai, General History of Kazakhs, was banned for publication in China. In this work, the author, as a historian and representative of the ruling nation in the country, gives an objective assessment of the history of Kazakhs who moved from Kumil (Hami) and Barkol regions of Eastern Xinjiang. Unable to bear the national oppression of local Chinese rulers and the violence of communist authorities, people migrated to Eastern Anatolia in search of freedom. This is one of the greatest tragedies in human history, of which little is known until now. Therefore, the data of this period and the role of research on them in revealing historical truth are special. Much of the information we use in this article to uncover the facts of this history is taken from previously unpublished original data from Su Beihai's manuscript. Even today, the problem of minorities in China is not completely solved. Thousands of indigenous people born and raised in Xinjiang still live abroad.