Abstract: Aiming at the mechanical properties of several geomembranes (GMs) commonly used as the main impervious materials of membrane-faced rockfill dam (MFRD), the uniaxial tensile tests, liquid expansion tests, local scratch resistance tests and capability to accommodate deformation tests are carried out. The test results show that compared to other GMs, the PVC-HX with the thickness of 1.0 mm is superior in the Young's modulus, linear elastic range of stress-strain and capability to accommodate deformation. Under the same scratch length, direction and ratio of depth to thickness, the TPO has strong resistance to the local scratch damage. However, the PVC-HX behaves satisfactorily in the ultimate strength against damage and the ultimate elongation, which can meet the mechanical performance requirements of impervious structures of the GMs. The HDPE/PE with thickness greater than 0.8 mm has high stiffness, low capability to accommodate deformation and local scratch damage, therefore, it is not suitable for the impervious structures of the GMs under high pressure and porous medium cushion. The comprehensive results indicate that the PVC-HX and TPO with thickness greater than 1.0 mm have potential advantages in the impervious structures of high MFRDs, and the HDPE/PE is recommended when the thickness is less than 0.8 mm required in engineering design.