The Yan'an Rectification Movement (simplified Chinese: 延安整风运动; traditional Chinese: 延安整風運動; pinyin: Yán'ān Zhěngfēng Yùndòng) also known as the Rectification Movement (Chinese: 整風运动), Zhengfeng or Cheng Feng was the first ideological mass movement initiated by the Chinese Communist Party (CCP), going from 1942 to 1944. The movement took place at the communist base at Yan'an, a remote and isolated mountainous area in northern Shaanxi, after the communists' Long March. Though it was during the Second Sino-Japanese War, the CCP was experiencing a time of relative peace when they could focus on internal affairs.
More than 10,000 were killed in the "rectification" process, as the Party made efforts to attack intellectuals and replace the culture of the May Fourth Movement with that of Communist culture.
The legacies of the Yan'an era proved fundamental to the subsequent history of the Chinese Communist Party, according to Kenneth Lieberthal. These included the consolidation of Mao's paramount role within the CCP, especially from 1942 to 1944, and the adoption of a party constitution that endorsed Marxist-Leninism and Mao Zedong Thought as guiding ideologies. This move formalized Mao's deviation from the Moscow party line and the importance of Mao's major adaptations of communism to the conditions of China. The Rectification Campaign was successful in either convincing or coercing the other leaders of the CCP to support Mao. Because the CCP had overcome great odds to grow and develop during this period, the methods employed in Yan'an were looked upon in reverence during Mao's later years. After the founding of the People's Republic of China in 1949, Mao repeatedly used some of the tactics that had been successful in Yan'an whenever he felt the need to monopolize political power. In large part, the Yan'an Rectification Campaign began with the "systematic remolding of human minds."