Photocatalytic efficiency enhancement through the construction of heterostructure interface in traditional materials is remain a significant challenge. In this paper, the photocatalytic properties of LaBO₃/KNbO₃ (B = Al, Ga，abbreviated as LBO/KNO) interfaces were investigated by building sandwich-like p-n type KNO/LBO/KNO heterostructures. Through the analyses of band alignment, the LaBO₃/KNbO₃ heterostructures with KO–KO, KO–NbO₂, NbO₂–KO and NbO₂–NbO₂ terminal can all be promised as photocatalysts for reduction reactions. Compared with the KO–NbO₂ and NbO₂–KO terminal, the absorption spectra of KO–KO terminal and NbO₂–NbO₂ terminal show obvious absorption peaks in visible-infrared region for LaBO₃/KNbO₃ heterostructures. With increasing the number of KNbO₃ layers, the width of the pseudo band gap gradually decreases leading to a bathochromic shift of absorption peak. The absorption band eventually moves from ultraviolet to visible and infrared regions, which accounts for 92% of the total solar energy. Benefited from the construction of p-n heterojunction with special sandwich-like structure, the absorption photon achieves the energy interval modulation. Moreover, the unique LaBO₃/KNbO₃ interfaces enhance the absorption bandwidth and efficiency of solar energy, which may provide a novel pathway for design high-performance photocatalytic materials.