1840—— 1860 The milestone of China's initial entry into semi-colonial and semi-feudal society: the Opium War broke out and the treaty of nanking was signed.

1860—— 1895 An obvious milestone in the semi-colonial and semi-feudal degree of China: the Second Opium War broke out and the Beijing Treaty was signed.

1895—— 1900 A serious milestone in the semi-colonial and semi-feudal degree of China: the defeat of the Sino-Japanese War and the signing of treaty of shimonoseki.

1900—— 1949 The milestone of China's complete entry into semi-colonial and semi-feudal society: Eight-Nation Alliance invaded China and signed the "Xin Chou Treaty".