The invention discloses a shutdown point optimization method for a main engine of a spacecraft, and belongs to the field of orbit transfer control over space orbit transfer vehicles. The motion of the spacecraft is analyzed under an orbit-insertion point orbit coordinate system, the adjustment amount of gliding time is introduced to adjust the shutdown point, control similar to feedback control in the classical control theory is adopted to correct errors till the errors meet the precision requirement, and the position of the shutdown point is obtained. By means of method, the influence of unmet terminal position constraints caused by the nonadjustable thrust of the main engine is reduced, the shutdown point can be adjusted according to the change of flight missions, and thus the precision of the orbit-insertion point is improved; besides, the method has high adaptability to large system deviation.