A performance analyzing model of Ygroove liquid film seals was established based on mass conserving boundary condition.The universal Reynolds equation was discretized by the finite difference method,and loadcarrying capacity,film stiffness,leakage,friction torque were obtained by solving the discretized equation with the SOR iterative algorithm.The influence of structural parameters of Ygroove liquid film seals on the seal performance were analyzed.The results indicate that the sealing performance is significantly affected by structural parameters,including the number of grooves,groove depth,spiral angle,ratio of groove to ridge width and ratio of groove to groove.With the increasing of these structural parameters,the load-carrying capacity and film stiffness are first increases then decreases,the friction torque is increased.The leakage is first increased then becomes steady with increasing of groove number,first increased then decreased with increasing of ratio of groove to ridge width,and decreased with increasing of ratio of groove to ridge width.The Ygroove liquid film seals have better performance with the parameters in the paper:the number of grooves is from 12 to 14,groove depth is from 35 to 40 μm,spiral angle is from 12° to 16°,ratio of groove to ridge width is from 0.7 to 1.1,and the ratio of groove to groove is from 0.8 to 1.0.