To improve space target tracking precision and the stability of mobile optoelectronic tracking equipment, an error-space estimation method based on the Kalman filter is discussed, and a simplified algorithm is presented to reduce calculation cost. Based on an available measurement of a space target without sufficient validity and accuracy, the actual position related to the tracking equipment is decomposed to an earlier offline prediction of the kinetic model method and prediction errors. By regarding prediction errors as the motion of a weak maneuver target, the errors can be estimated more accurately in error space. By synthesizing estimation of the errors and offline prediction, the space target position is obtained with higher accuracy to improve tracking performance.