The invention provides a spacecraft orbit maneuver motor installing parameter optimizing method based on a Runge-Kutta algorithm. According to the method, firstly, each coordinate system is defined; then, a mathematical model between undetermined coefficients and a vector from a theoretical circular center A of a motor installing flange to a theoretical circular center C of the motor installing flange is built; a vector from the circle center A to a target point T, a vector from O<s> to the circle center A, a motor thrust vector F<EB>, an acting point position vector, a vector from the circle center A to the target point T, a vector from the circle center A to the motor thrust vector acting point P, a motor thrust vector and a vector from the motor thrust vector acting point P to the target point T are sequentially calculated; and after the undetermined coefficients are solved, the installing angle and the installing position are obtained. The method has the advantages that the optimum design mathematical model is built; and on the premise that a solution meets the constraint condition, the optimum values of motor installing parameters meet the requirements of the spacecraft orbit maneuver motor installing parameter optimization to the maximum degree.