First, before the reunification of the Qin Dynasty, China experienced more than 300 years of the Spring and Autumn Period and the Warring States Period, and there was no unified concept in the hearts of ordinary people. Although the Qin dynasty unified all countries, the people of each country still longed to revive their country.
Second, after the Qin dynasty unified all countries, it implemented a cruel policy, and the people complained bitterly, which aggravated the contradictions. "Qin can't be punished", and people's opinions on the ruling class are growing, and finally a peasant uprising broke out.