One of the keys to the normal operation of the hydraulic rotary vane actuator（RVA）is the sealing reliability of the endseal.The mathematical model of the endseal of RVA in the static sealing condition was built.By solving the model,the contact pressure between the endseal and the rotor and stator was obtained.The contact pressure between the endseal and the rotor and stator was also solved by the Finite element software.The contact pressure obtained analytical method and finite element analysis method are similar at the pre compression from 0 to 0.5 mm and the oil pressure from 0 to 20 MPa,and the results of the prototype experiment also verify the correctness of the model when the precompression is 0 and 0.2 mm and the oil pressure is from 0 to 20 MPa.The analytical result shows that the established endseal model can be used to judge the seal reliability of the endseal in the static sealing condition.