1959年夏，毛澤東在廬山會議中發起「反右傾」，既引發黨內激烈的政治鬥爭，更讓「大躍進」益加惡性發展，造成經濟嚴重失調和大規模的饑饉死亡。當時經常參與最高決策、也負責將之落實的彭真，在「反右傾」中的關鍵角色和重要影響問題，一直未受到應有的重視。西方學者對此不甚了解，中共官方所撰的彭真傳記也刻意避重就輕。這段時期代替鄧小平主持中央書記處工作的彭真，在廬山會議期間和其後，皆竭力配合毛澤東，作為「反右傾」的主要執行者。彭真在廬山上積極響應毛對彭德懷等人展開的政治批鬥；返回北京後，他負責督導、推促中央黨政部門、軍隊、首都北京市，以及高校的「反右傾」運動。從上述的政治過程中，可以增進對彭真個人以至中共相關的政治事件和歷史的認識。 In the summer of 1959, Mao Zedong launched the Anti-Right Opportunist Campaign in the Lushan Conference. Not only did it lead to a severe intra-Party power struggle, but also allowed the Great Leap Forward to enter its second round in 1960, further devastating the fragile economy. At that time, Peng Zhen was greatly involved in CCP decision-making and policy-implementation. However, Peng's crucial role in the Anti-Right Opportunist Campaign has received very little attention from Western publications. In addition, Peng's official biography written by the Chinese Party historians tried to downplay his role and responsibility for this notorious campaign. This study demonstrates the following: during and after the Lushan Conference, Peng followed Mao closely and he proved himself particularly active in running the campaign. In Lushan, Peng zealously responded to Mao's criticism toward Peng Dehuai; shortly, back to Beijing, he was in charge of directing and supervising the Anti-Right Opportunist Campaign in the Party and government departments, the military, the Beijing city and the institutions of higher education. This study enhances the understanding of Peng's political career and the Chinese politics during Mao era.