Abstract: To develop a high performance, recyclable, low cost photocatalyst. In this work, MoS₂ modified ZnO (MoS₂-ZnO) nanocomposites were prepared by a hydrothermal method. The morphology and optical properties of the samples were characterized by XRD, SEM, photoluminescence spectroscopy (PL) and XPS. We find that the prepared MoS₂-ZnO samples own a porous structure from SEM. And MoS₂ can not only enhance the separation efficiency of photocarriers in MoS₂-ZnO, but also increase the absorption of visible light region, resulting in improving the photo-catalytic and gas sensitive properties. Under simulated sunlight, the MoS₂-ZnO nanocomposite exhibits high photo-catalytic degradation activity for high concentration (15 mg/L) methylene blue dye (MB). At the same time, the MoS₂-ZnO-based gas sensor possesses a high sensitivity for NO₂ concentration of 2.05 mg/m³. This work offers a simple strategy to prepare highly efficient visible light-driven photocatalysts and gas sensors.