There are three specific reasons:
1. China's sovereignty began to be undermined. Before the war, China was politically a country with territorial integrity and sovereign independence. Clauses such as the cession of Hong Kong after the war destroyed the territory and territorial sovereignty outside Zhong. The system of "consular jurisdiction" destroyed the judicial sovereignty of China, negotiated tariffs, and damaged the tariff sovereignty of small countries; One-sided MFN treatment facilitated the large-scale plundering of China by foreign powers. In this way, China began to change from an independent sovereign gardener to a semi-colonial country enslaved by foreign invaders.
2. China's self-sufficient natural economy began to collapse. Before the war, China was a feudal country based on natural economy. The combination of small-scale agriculture and cottage industry effectively excludes the invasion of foreign commodities. After the war, the "public treasury" system was abolished, the number of trading ports increased, and tariff sovereignty was lost. Cheap foreign goods keep pouring into China. This kind of commodity "heavy artillery" gradually destroyed China's self-sufficient feudal economy, and made China increasingly become the commodity market and raw material supplier of foreign capitalism.
3. The social class structure and principal contradiction in China began to change. Before the war, there were basically only two opposing classes in China, namely, the peasant class and the landlord class. After the war, a number of comprador and comprador businessmen appeared. The first batch of industrial workers appeared in foreign companies. The main contradiction in China society is not only the contradiction between the original feudal landlord class and the people, but also the contradiction between foreign capitalism and the Chinese nation. Since then, the China Revolution has entered a new historical period with anti-imperialism and anti-feudalism as its main task.