Abstract: Molybdenum disulfide (MoS₂) was introduced into the polyacrylamide/chitosan (PAM/CS) hydrogel system by free radical polymerization, and the PAM/CS/MoS₂ composite polymer hydrogel with interpenetrating network structure was prepared. The composition and morphology of the hydrogels were analyzed by Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, and laser scanning confocal microscopy. The mechanical properties and hydrophilic properties were tested by a universal testing machine and a contact angle measuring instrument. Finally, the application of the composite hydrogel film in the field of humidity sensing was explored by a quartz crystal microbalance (QCM). The PAM/CS/MoS₂-0.4 (mass of MoS₂ in this system is 0.4 mg) composite hydrogel has a maximum compressive stress of 584.6 kPa and a maximum compressive strain of 83.8%. The introduction of MoS₂ improves the hydrophilicity of the composite hydrogel. As the relative humidity of the environment increases from 11% to 95%, the frequency response of the QCM humidity sensor modified by the composite hydrogel film reaches a maximum of 2642 Hz, and its sensitivity of 1% change of relative humidity is 31.45 Hz, which is expected to be applied in the field of humidity sensing.