知识分子历来都不是独立的阶级，只能依附一定的阶级。因此，正确判断知识分子的阶级属性，就成为认识和解决知识分子问题的关键。毛泽东晚年把知识分子划归资产阶级范畴，这是一个原则性的失误，并成了他后来犯阶级斗争扩大化错误的关键因素。毛泽东对知识分子阶级属性判断失误的原因是复杂而多种多样的。总的说来有两个方面：对知识分子整体思想政治状况估计失误、匈牙利事件与反右斗争的影响，是导致毛泽东在这一问题上失误的现实原因；而他在知识分子问题的理论上的一系列矛盾与困惑，则是在这一问题上出现失误的深层次原因 Intellectuals have never been independent class, can only attach to a certain class. Therefore, correctly judging the class nature of intellectuals has become the key to understanding and resolving the issue of intellectuals. Mao Zedong’s classification of intellectuals in the bourgeois category in his later years was a mistake of principle and became a key factor in the mistakes made by him in later attempts to enlarge the class struggle. The reason why Mao Zedong makes mistakes in judging the class nature of intellectuals is complex and varied. In general, there are two aspects: the overall intellectual and political situation of intellectuals mistakes in the estimation, the events of Hungary and the anti-rightist struggle is the real reason for Mao Zedong mistakes in this issue; and he in the theory of intellectuals A series of contradictions and confusion, it is the deep-seated reasons for mistakes on this issue