China’s foreign trade has developed sustainably in the unity of opposites between continuity and stages since 1949. China's opening up to the outside and foreign trade can be divided into four different stages roughly from 1949 to 2019. The situations at home and abroad, the policies, the development characteristics and the results were not all the same in each stage. They even had big differences. Some special measures may be opposite. However, the principle of adhering to opening to the outside world and developing foreign trade actively had never changed. Foreign trade as a whole was continuously expanded and deepened, and ultimately it had achieved good comprehensive results.