To reveal the error propagation rules of camera geometric specification in stereoscopic mapping more accurately, the relationship between the mapping accuracy and specification difference parameters of dual-linear-array CCD camera is studied. Aiming at the characteristic of dual-linear-array stereoscopic mapping, effects of the geometric specification difference parameters on mapping positioning are analyzed. Based on the space forward intersection formula, the positioning accuracy (PA) model is established, and then the variations of PA with the difference between calibration errors of interior orientation elements are presented. The results show that the effect of the difference between principal point x errors on PA is obvious, and the PA rapidly decreases by 60% when the difference change increases to 2.5 μm from 1 μm. In addition, the effect of the difference between focus length f errors on PA can be almost neglected. The model and relevant conclusions have important guiding meaning for the optimization design and quantification of dual-linear-array CCD camera specification.