•The chemical vapor deposition method realizes the controllable preparation of uniform γ-In2Se3 nanosheets.•Growing γ-In2Se3 nanosheets on SiO2/Si substrates can avoid potential contamination and damage during the transfer process.•The prepared γ-In2Se3 based photodetector has a stable broadband optical response. Display omitted Two-dimensional (2D) In2Se3 with excellent optical and electrical properties has great application potential for flexible devices, photodetectors, and phase change memories. Here, we report the successes of growing In2Se3 nanosheets on SiO2/Si substrates by chemical vapor deposition (CVD) and fabricating broadband photodetector based on In2Se3. The Raman spectroscopy and transmission electron microscopy studies indicate that our 2D In2Se3 is in γ-phase. Our 2D γ-In2Se3 photodetector shows a broadband response range from near ultraviolet (350 nm) to infrared (1000 nm). The stable broadband response provides opportunities for the application of 2D γ-In2Se3-based devices and also a reference for the preparation and application of other 2D materials.