In this work, the dense γ-In2Se3 nanosheets array has been fabricated using chemical vapor deposition method under atmosphere pressure. Compared with crystal silicon, the photodetector based on γ-In2Se3/ p-Si heterojunction exhibits a high responsivity (96.7 mA W-1) at near-infrared region, a presentable current on/off ratio (∼1000) and an excellent detectivity (2.03 × 1012 jones). Simultaneously, the obtained photodetector performed fast response speed (0.15ms/0.5ms) and a broadband sensitive wavelength from ultraviolet (340 nm) to near-infrared (1020 nm). The photoelectric experimental data of the device shows that its high performance is attributed to the high light absorption capacity of the material, the rational energy band structures of γ-In2Se3 and p-Si, and the effectively separation of photo-generated carriers caused by the formed type-II heterojunction. Our work provides primary experimental basis for the photodetection application of γ-In2Se3 nanostructure.