Because the communist ideal is an achievable social ideal. According to relevant public information, the communist ideal is an achievable social ideal. Communism is not far away. Marxism's prediction of social development is by no means a utopian fantasy, but a new socialist society has been discovered in the analysis of capitalist society. It is from the aspects of productivity, production relations, social life and spiritual life, their dialectical relationship and future trend that the basic characteristics of communist society are grasped. Through in-depth study of capitalist society, especially capitalist economic movement, Marx discovered the basic contradictions in capitalist society, namely the socialization of production and the private possession of means of production. Through the analysis and dynamic study of this contradiction, Marx further revealed many contradictions such as class contradictions and international contradictions derived from the basic contradictions in capitalist society, as well as various crises such as economic crisis, political crisis and social crisis, thus revealing and demonstrating the historical temporality of capitalism and scientifically predicting capital. Not only that, Marx also found the proletariat, the main force to bury the old capitalist system and build communism. The discovery of this power is also obtained by analyzing the characteristics of capitalist mode of production.