The two-volume set CCIS 2910 + 2911 constitutes the refereed proceedings of the 20th CCF Conference on Computer Supported Cooperative Work and Social Computing, ChineseCSCW 2025, held in Guangzhou, China, in November 2025.The 50 full papers and 13 short papers presented in the proceedings were carefully reviewed and selected from 196 submissions.These papers were organized in topical sections as follows:Part I: CSCW and Social Computing and Human-Machine-Things Fusion and Human-AI Collaborative Computing.Part II: Crowd Cooperative Computing and Evolutionary Computation and Collaborative Data, Software and Services.