This paper reports the lateral photovoltaic effect and applications of WSe?/Si heterojunctions. High-quality WSe? films were grown on p-type and n-type Si substrates using pulsed laser deposition. The quality of the prepared WSe? films was verified through X-ray diffraction patterns, X-ray photoelectron spectroscopy, and Raman spectroscopy. The vertical I-V characteristics of the heterojunctions exhibited distinct unidirectional conductivity and high open-circuit voltage. When a point light source moved across the WSe? surface, the voltage difference between the two electrodes showed a linear relationship with the light spot position. The lateral photovoltaic relaxation times for WSe?/p-Si and WSe?/n-Si heterojunctions at 393 K were 1.1 μs and 1.92 μs, respectively, suggesting new possibilities for developing high-temperature stable sensors. Additionally, we investigated the image sensing capabilities of these heterojunctions under low-light conditions.