Confucius lived more than two thousand years ago. Due to the limitation of objective conditions such as times and subjective conditions, his ideal of great harmony society is very vague and abstract, which has serious limitations. The blueprint of Datong society he described is different from scientific socialism and communism. Confucius' ideal society of great harmony is only an idealization of Yao and Shun's social conditions, that is, an idealization of primitive society, which is not qualitatively different from primitive communist society. He doesn't understand that "great harmony" is an advanced social form and the most ideal realm of human society. It is not a return, but a great progress. Therefore, the purpose of Confucius is only to gradually return the society to a society similar to the primitive commune state. It is even more impossible for him to understand the decisive role of economic base, the contradiction and struggle between productivity and mode of production, and the economic base and superstructure promote the development and evolution of social form, which can only improve people's moral level. Ignoring the improvement of productive forces and the material foundation, it is impossible for the world to achieve "great harmony" As for how to build such an ideal society, Iraq is even more ignorant. He never pointed out a correct and feasible path.