In the paper, a g-C3N4/MoS2 humidity sensor with high response, low hysteresis and fast response/recovery for skin health status detection was prepared. The synthesis of g-C3N4/MoS2 heterojunction materials increases the interfacial barrier and improves the sensitivity of sensor. The edge unsaturated bonds and S defects of g-C3N4/MoS2 composites together enhance the adsorption of H2O, which in turn improves the sensitivity of sensor. The consequent acceleration of electron transfer between the material surface and water molecules led to an improvement in the response/recovery speed and humidity hysteresis. The N-H on the composite surface promotes the formation of physically adsorbed water layer and enhances the sensor recovery capability. The g-C3N4/MoS2 sensor shows high sensitivity (204875 Ω/%RH), fast response/recovery speed (11/9 s), and low hysteresis (2.0 %) at the 11 %-95 % RH range. In this study, the sensors were successfully used for the detection of skin health conditions, providing a viable solution for skin detection.