Adding a common point feature which provided spatial geometric constraints,the paper analyzed the number of solutions to monocular vision pose measurement based on a circular target and a non-coplanar point. The geometric method was used to prove that the number of solutions is determined by the relative position of the feature point,the optical center and the circle plane,then a new algorithm was proposed to measure the pose and orientation. The algorithm can determine the six dimensional pose parameters,and the results of simulation and experiments indicated the effectiveness and accuracy.