In the process of the formation and development of the fine style of criticism and selfcriticism, the exploration of Mao Zedong in Yan’an period on criticism and selfcriticism took prominent position. In Yan’an period, Mao Zedong made the forceful exploration on criticism and selfcriticism mainly from such three dimensions as the functional dimension, approach dimension and practice dimension. Currently, under the situation of anti“fouradversestyle”, the careful study of Mao Zedong in Yan’an period on the exploration on the three dimensions of criticism and selfcriticism is of importantly real enlightenment on a thorough investigation, a thorough examination and rectification, and a thorough elimination for the “fouradversestyle”