A weighted iterative pose estimation method is proposed, which combines the object-space errors and image-space collinearity errors. Based on the efficient perspective-n-point (EPnP) algorithm, an improved iterative algorithm with adaptive weighted object-space collinearity error function is added to optimize the results, and the average image-space collinearity error after iteration is used as the minimum error decision threshold to correct the parameters with relatively large errors. The experimental results show that this proposed method can greatly improve the accuracy and robustness of the pose parameters of the EPnP algorithm in the non-redundant situations. Moreover, it can maintain the high precision of the EPnP algorithm and possess high practical value in the condition of sufficient reference points.