Considering the estimation degradation caused by the pure rotational movement in the monocular vision system and the motion parameter constraints,we proposed an OPA-based spatial-time constraint pose estimation algorithm for monocular vision systems.The OPA algorithm was used to detect and correct the estimation degradation before estimating the essential matrix and translational direction vector.Combined with the time-related constraints of camera in motion process and the space-related constraints of image feature point,the estimation to navigation parameters of the monocular vision system were obtained.Comparative analysis of two sets of experimental results shows that the proposed algorithm has higher accuracy and stability compared with the conventional estimation algorithm.