Abstract: Pleural effusion(PE) is a common medical problem with various causes. The differential diagnosis for PE is often challenging. This consensus was generated by members of the academic group of the pleural and mediastinal diseases(preparatory) of Chinese Thoracic Society and some external experts. The members convened in virtual meetings and conducted an extensive literature investigation and assessed the quality of the evidence using a modified grading of recommendations assessment, development, and evaluation(GRADE) approach. This consensus included three chapters: the initial evaluation of PE, the diagnosis of PE with common causes, and the diagnosis of PE with uncommon causes.