In order to complete the numerical simulation on internal flow and operating characteristics of down hole multiphase pump compress unit, establishing perfect finite element model, the three-dimensional turbulent current fields inside the impellers of compression unit for down hole multiphase pumps were simulated by using ANSYS. The calculation of multiphase flow is based on the standard k-ε turbulent current model. Reference information for the improvement of the pump can be obtained by the analysis of the flow of gas-oil in the channel of pump. Based on the finite method, we analyzed several situations in a pumping period. The velocity and liquid pressure distributing of sucker rod pump is studied in this paper, which may offer some evidences for the engineering design of sucker rod pump.