1. The root cause: in the late Qing Dynasty, the feudal dynasty was tired. Although there are prosperous times, it is just a glowing lamp. At this time, the mainstream of the times is capitalism, so the replacement of feudal society is an inevitable historical event.

2. Politics: the darkness and decay of the Qing government. Its representative figure is Cixi, who even celebrated her birthday, making the military expenditure of the new army a gift for her. This also led to the joke that our fleet didn't even have shells during the Sino-Japanese War.

3. Economy: Self-sufficient small-scale peasant economy restricts social development and progress. The commodity economy has been suppressed. Leading to backward economic development. When all countries in the world completed the industrial revolution, China was still a natural economy with men plowing and women weaving.

4. Culture: imperial examination system, stereotyped writing of literati, which limits people's thinking. Leading to backward technology.

There are other reasons, closed doors, colonization and civil strife.