Abstract: Some embodiments of the present disclosure provide a back structure of a solar cell. The back structure includes an aluminum oxide film layer disposed on a silicon wafer substrate, and a first silicon nitride film layer and a first silicon oxynitride film layer, which are successively disposed on the aluminum oxide film layer from inside to outside; and the back structure further includes a second silicon nitride film layer disposed on the first silicon oxynitride film layer. The refractive index of the first silicon nitride film layer is greater than that of the second silicon nitride film layer, and the refractive index of the second silicon nitride film layer is greater than that of the first silicon oxynitride film layer.