Aimed at the problem that the fluid bearing capacity of liquid lubricated noncontacting mechanical seal is insufficient in low viscosity environment,a new type of spiral groove and wavytiltdam combined mechanical seal structure was proposed,and its sealing performance was compared with that of spiral groove,wavytiltdam respectively.The finite difference method was used to solve the Reynolds equation considering massconserving cavitation boundary conditions by using MATLAB software.The influence of different structural parameters and working conditions on the performance parameters of combined mechanical seal was further analyzed.The results show that when the wave number of the new groove coincides with the number of spiral grooves,the combined groove structure has two pressure peaks in the radial direction,which has better loadcarrying capacity and smaller friction torque than the single groove structure.The liquid film force and leakage are increased with the increase of wavecone ratio or radial width ratio,and the larger the external diameter pressure and rotational speed,the higher the loadcarrying capacity of the combined groove.The larger radial leakage will be caused by the increase of the external diameter pressure.The combined seal combines the advantages of the static pressure bearing of the wave cone groove and the dynamic pressure bearing of the spiral groove,which will effectively improve the lubrication performance of liquid lubricated noncontacting mechanical seal in the low viscosity environment.