Digital camera is non-metric camera. Its geometric calibration, including the determination of interior orientation elements and distortion parameters, is the base of high precision photogrammetry. In this paper, a laboratory geometric calibration system of digital cameras is developed. This system uses a collimator and a star tester as the target generator. After high precision positioning of targets and corresponding angles of parallel lights, geometric calibration can be accomplished according to the method of this paper. Experiments are taken out based on this system using two kinds of mainstream digital aerial cameras, Cannon EOS 5D Mark II and Hasselblad H3D, and the repeatability experiment is also taken out. Experiment results show that this system can satisfy the calibration requirements of photogrammetric application and the correctness and reliability of the measure precision of this system is verified.