War is an important reason for emigration in China's history.

There are two main reasons for emigration. One is official, not spontaneous.

There are three main reasons for official immigration. First, one area has a relatively small population while another area has a relatively large population, which is mainly caused by war, such as the great migration of Zhu Yuanzhang in the early Ming Dynasty and the "Huguang filling Sichuan" in the early Qing Dynasty. The second is to compete for population during the war. For example, Zhuge Liang of Shu Han came out of Qishan, and after the defeat, he pulled people from three counties into Shu. The third is to force local strongmen to emigrate, which is convenient for management. For example, after the reunification of Qin Shihuang, Six big noble was pulled into Xianyang.

There are two main reasons for spontaneous migration. First, there is no livelihood for two reasons. One is war, and the other is famine, such as crossing the Kanto. Second, alien rule, such as Yongjia Du Nan.

It is reasonable to say that immigration is because of war, but it is not complete.