Provided in the present application are a heterojunction cell and a method for preparing same. The heterojunction cell comprises: a semiconductor substrate layer; and an intrinsic semiconductor composite layer, wherein the intrinsic semiconductor composite layer is located on the surface of at least one side of the semiconductor substrate layer, and the intrinsic semiconductor composite layer comprises: a bottom intrinsic layer; and a wide-band-gap intrinsic layer, which is located on the surface of the side of the bottom intrinsic layer that is away from the semiconductor substrate layer, the band gap of the wide-band-gap intrinsic layer being greater than the band gap of the bottom intrinsic layer. The band gap of a wide-band-gap intrinsic layer is larger, and when sunlight irradiates a heterojunction cell, photons, the energy of which is less than that of the band gap of the wide-band-gap intrinsic layer, cannot be subjected to parasitic absorption, thereby reducing the parasitic absorption of the sunlight by an intrinsic semiconductor composite layer, such that the absorption of the sunlight by a semiconductor substrate layer is increased, and photon-generated carriers generated by the semiconductor substrate layer are increased, thereby increasing a short-circuit current of the heterojunction cell, and improving the conversion efficiency of the heterojunction cell.