According to the requirements of hydraulic pressure controlling system of the State 863 Plan of China: “the development of cased hole twin packer cell”, a new type of two-way valve used in the hydraulic pressure controlling system of downhole tester was developed, which could control the direction of liquid movement. The valve has not only the sealing function of seal valve, but also the adjustment function of the rate of flow of throttle valve. It is different from the ordinary two-way valve in structure because of its particular demands of function and performance. In this paper, a study was carried out on the flow field and flow characteristics in the throttle control valve by means of hydromechanics numerical simulation and with the resulting analysis, structural optimization was performed to the throttle control valve. The result that obtained by simulation calculation can provide theoretic reference for the valve design.