Aiming at the problem that robot calibration is highly configuration dependent, considering the correlation of the approximation degree of vectors versus the distances and angles among different position vectors at the end of the robot, as well as the triangular area formed in space, the concept and measurement method of the approximation degree of robot pose and pose error vector are introduced, and the discriminating rules and using conditions based on the approximation degree are formulated. Furthermore, the database samples in the neighborhood of the target pose are screened. On this basis, a robot accuracy compensation method based approximation degree weighted average interpolation is proposed. The sample point pose and error data screened in the workspace are used to predict the interpolation values of the pose error of the target point. The example study results show that the proposed method can effectively improve the spatial adaptability of the robot pose error compensation and meet the requirements in highend field.