In order to improve the efficiency of digital zenith camera, the orientation method was studied on the basis of precision position. Coordinate transformation model for identified star points was constructed. Then the coordinate transformation model was analyzed. The effects of instrument tilt and optical axis tilt on star points were analyzed respectively. Influence of focal length and astronomical coordinates of optical axis on the theoretical image coordinates of star points were also studied. Then the orientation model was established based on coordinate transformation. Analysis of experimental data shows that the orientation accuracy of single group star images is within 5″. The orientation accuracy is high, which can meet the requirements of orientation accuracy under actual conditions.