According to the configurations of optical system in a three line array mapping camera, a new optical system integrated with excellent features by Petzval and symmtry was designed based on a telecentric path to meet the requirement of stereoscopic mapping.The system shows a good imaging quality, and the MTF value of each lens is close to the diffraction limit at the Nyquist frequency of 77 lp/mm. Furthermore, the distortion of each optical system is less than 2.0×10-5 for the straight-sight camera and 2.4×10-5 for forward-sight and backward-sight cameras. Sensitivity analysis and inverse sensitivity analysis were used to compute the effect of each tolerance parameter on the optical system performance, and the proper tolerance requirements and compensators were determined.On the basis of tolerance given, the optical system with high image quality and low distortion was fabricated and assembled. The tested result shows that the MTF of each optical system can reach 0.451 at the Nyquist frequency of 77 lp/mm, which meets the requirements for static MTF more than 0.2 and relative disortion less than 3×104 and proves that tolerancing analysis methods are correct and feasible.