The invention discloses a copper zinc tin sulfur film solar cell device based on a polyimide flexible substrate. The solar cell device is characterized in that: 1, a polyimide flexible substrate film solar cell has a quite high weight-power ratio (W/kg), i.e., the solar cell per unit of weight can emit a larger electric quantity; for curved-surface modeling of a ground photovoltaic building and a mobile photovoltaic power station, the flexible substrate film solar cell has the advantages of flexibility, foldability and crash resistance; and the flexible substrate cell has the maximum potential in reducing the cost and is suitable for a roll-to-roll technology of large-scale production; and 2, each composition element, i.e., copper, zinc, tin and sulfur is abundant in reserve and pollution-free to environment, and the preparation cost is low; the band gap of the copper, zinc, tin and sulfur is about 1.45eV, which is very close to the ideal band gap of 1.4eV; the copper, zinc, tin and sulfur is a direct band gap p-type semiconductor material, the optical absorption coefficient exceeds 10<4>cm<-1>, and the copper, zinc, tin and sulfur is quite suitable to serve as the absorption layer material of the film solar cell; and the cell conversion efficiency is high, and the highest conversion efficient of a single-junction cell can be reached theoretically. The advantages are as follows: the cell preparation method is simple and easily implemented, large-scale popularization and application are facilitated, and the device and the method have extremely important application prospect especially in space and special occasions.