After careful reading a series of Mao Zedong’s manuscripts during the socialist period,it is not difficult to find that Mao Zedong focused on the use of class struggle point of view in observing and considering the class relationships of domestic society,the cause of a small number of people to make troubles,the status of democratic Parties and intellectuals,the trend of domestic thoughts and many other social issues,etc,which led Mao Zedong to take the domestic situations too seriously.This made Mao Zedong fail to rightly treat the criticisms during the movement of "rectification of incorrect styles of work" and "airing of views",and make the decisions to launch the anti-rightist campaign.It could be said that making decision to launch anti-rightist campaign was the use and practice of Mao Zedong’s leftist guiding ideology of "taking class struggle as the key link",which deeply existed in Mao Zedong’s thought.