Aiming at improving the accuracy and stability of the pose estimation when the target points located in the planar, quasi-planar and quasi-linear case. In this study, we propose an iterative solution for singular configuration of target points. The main idea of the algorithm is to select two farthest points as the basic reference points, and divide n points into n-2 three-point sets. Then, the auxiliary points are constructed according to the geometric relationship of the three-point set, aiming to increase the geometric constraints of the perspective similar triangle algorithm, and obtain a more accurate initial value. Finally, the simplified EPnP algorithm is combined with Gaussian Newton algorithm for optimization. Experiments conducted on synthetic data and real images show that when the number of planar target points n=4, the average image re-projection error of this algorithm is 0.003 mm, compared with the orthogonal iterative algorithm, EPnP algorithm and IEPnP algorithm, which is 0.062 mm, 0.324 mm and 2.238 mm respectively, this algorithm effectively improves the accuracy and stability of the pose estimation of the target point in singular configuration.