Interfacial electronic properties are greatly significant to study the photoelectric properties of semiconductor heterostructures. The novel heterostructures are constructed using perovskite 3D CsPbX3 (X = Cl, Br, I) and 2D PtSe2, and the structural and photoelectrical properties are studied by density functional theory. The band levels transform and interfacial charge transfer have serious differences at the interface of the CsPbX3-PtSe2 heterostructures. The CsPbCl3-PtSe2 and CsPbBr3-PtSe2 heterostructures show the type-I band arrangement, however, the CsPbI3-PtSe2 heterostructure demonstrate the type-II band arrangement. The difference in work function of the two semiconductors causes electrons to flow spontaneously at the interface. Moreover, the monolayer PtSe2 can broaden the absorption spectrum of the CsPbX3-PtSe2 heterostructures, that effectively enhance absorption capability of the heterostructures, especially the CsPbI3-PtSe2 heterostructure. These results demonstrate PtSe2 semiconductor materials can effectively improve the photoelectric performance of all-inorganic metal halide perovskite.