According to the leakage characteristics of the scroll tooth of scroll compressor, a mechanism model of sealing was presented in order to realize the sealing of axial clearance.The mechanism model consists of the seal element,and the seal element is made of self-lubricating materials and spring and is installed into the seal groove of scroll tooth.Through analyzing the differential pressure force of different positions, there are two kinds of working conditions for seal element,including with differential pressure condition and without differential pressure condition.The simplified mechanical model of the sealing mechanism was established according to the different working conditions,respectively.Through force analysis of the seal element and the orbiting scroll,the working process of the sealing mechanism under the action of the spring force,pressure difference and back pressure force of the orbiting scroll was studied.The structure design of the sealing mechanism was discussed in the light of the force analysis results in order to insure the normal work of sealing mechanism,and the structural parameters’ ranges were obtained,including the spring displacement,the seal groove depth and the diameter of back pressure cavity.