Abstract: The beam pointing stability in coude optical path is a key factor for the optical axis pointing accuracy of the laser range finder. By coordinate transformation, a dynamic method was developed to characterize the beam pointing stability in geometric space. A dynamic beam pointing error model in coude optical path for an altitude-azimuth laser range finder was built as an example, which was used to describe the relationship between the system error in the mechanical structure and the beam pointing error in coude optical path. A image collection system, consisting of an image acquisition card and a CCD mounted on the interface of the 5th coude mirror, was used to collect laser beam spots, and then, the high precision measured data of the beam pointing error was obtained. After least square fitting, the dynamic characteristic of the beam pointing error in coude optical path was finally calibrated, which would lay a foundation for the correction of the system error.