In various humanoid robot research areas such as biped walking and balance maintenance, control of Center of Mass (COM) is frequently used. However, it becomes a complex problem to directly control the COM for a high degree of freedom humanoid robot, especially in case of double feet support. In this paper, an iterative method that is easy to implement is proposed. Based on the approximated assumption that COM is fixed in local coordinate system, the control angle of the robot leg can be solved to drive the COM toward the target position. This process can be iterated to achieve high precision. Simulation tests on a NAO humanoid robot have demonstrated that the algorithm is efficient and precise.