The system is developed to digitize the trajectory camera photo plates and analyse the images accurately and automatically to replace the manual work which is poorly efficient. The system digitizes the plates by common flat scanner,calibrates the scan images accurately and analyses the images with digital image processing technology. The method of full-field accurate calibration only with orth-crossed griddings around the measuring images is described and the experimental results are shown. After the calibration, the full-field standard deviation is less than 2～3 μm. The system and the method of scanner calibration realizes the trajectory camera photo plates' digital, automatic and accurate analysis and makes it possible that common scanners is used in the engineering measurement, where high precision is demanded.