A liquid film seal device was designed to solve the problem contributed by motor’s lubricating medium leakage to motor winding at special conditions such as high speed rotation and positive and negative rotation.The finite difference method was used to discrete the Reynolds equation in the cylindrical coordinate system and the film pressure distribution of end face was obtained by using SOR solver.The variation of pumping performance,bearing capacity and leakage with the rotation speed and film thickness were compared for the liquid film seals with fir tree groove and T groove.Results show that the pressure peak value of fir tree groove seal is larger than that of T groove seal under the same conditions.Fir tree groove seal can realize the antipumping of leakage medium completely in lower speed or larger film thickness.The opening force of fir tree groove seal is larger than that of T groove seal under the same film thickness,and the opening force of fir tree groove seal changes obviously with the rotation speed and film thickness.It should be given priority to fir tree groove on the motor liquid film seal in comprehensive analysis.