As a software problem, the basic marriage problem may not be of great significance, but A Dream of Red Mansions is different from any other works with the basic marriage problem as the theme. It relates to the whole society and social system, vividly shows the sharp struggle between the oppressed class and the ruling class, exposes the inevitable trend of decadent feudalism, and eulogizes the weak but invincible new force. Through the analysis of the differences between the characters of Chai Dai and the identity of the tragedy of fate, the historical fate that feudal society is bound to collapse is profoundly revealed.