To overcome the low photocatalytic activity and efficiently harvest solar energy, a new type of composite photocatalyst PMo12/AgNPs is constructed based on polymolybdate (PMo12) and Ag nanosheets as the co‐active ingredient, and the composite material is characterized by FT‐IR, XRD, EDS, SEM, UV‐vis, EIS and PL. In this study, the controllable absorption range silver nanosheets with different sizes and morphologies are prepared by regulating the reaction condition, and the nanosheets further combined with PMo12 polyoxoanion to construct composite photocatalyst with efficient visible‐light response and photocatalytic activity. The EIS plots, Bode plots and PL spectra analysis results indicate that the PMo12/28 h‐AgNPs hybrid material exhibits excellent interfacial charge transfer efficiency and potential photocatalytic application. The photodegradation experiment of rhodamine B (RhB) is selected as the model reaction to evaluate the catalytic activity of PMo12/28 h‐AgNPs hybrid material under simulate visible light, in which the photocatalytic degradation98.75 % with pH=5 for PMo12/28 h‐AgNPs is higher than that of others. The .O2− and h+ are detected as active groups by different scavengers tests, and the possible photocatalytic mechanism of the composites is investigated.