Aviation hydraulic actuator is widely used in many parts such as aircraft wing, landing gear, hatch door, etc. The typical seal form is reciprocating seal, and the failure of seal will seriously affect the execution of flight mission and even flight safety. Therefore, simulation of seal has important theoretical and practical significance. This paper establishes a deterministic mixed lubrication numerical model for reciprocating combined seal, the fluid-solid coupling analysis is realized by combing finite element method (FEM) with fluid dynamics analysis. The effects of surface roughness and operating conditions on lubrication and sealing performance are investigated. The results show that increase of roughness and wavelength of three-dimensional sinusoidal rough surface can contributes to the increase of fluctuation amplitude of film thickness and pressure, and the reduction of friction. Increasing of amplitude of the sinusoidal rough surface is beneficial to the reduction of the minimum film thickness and leakage. However, the wavelength change has little effect on the minimum film thickness.