Abstract: The optical imaging system with large viewing angle, high resolution and low distortion is the most critical core device for the full-view and high-precision three-dimensional measuring instrument. The current 3D measuring instruments inevitably produce various errors in the actual use process. Therefore, it is of great scientific and engineering significance to evaluate and reduce the measurement errors producing by the full-view and high-precision 3D measuring instrument scientifically and reasonably.The influence of the camera calibration error of inner orientation elements on the geometric positioning error, and the effects of the modulation transfer function (MTF) analysis for the camera optical system, the point spread function(PSF) analysis, the wave aberration and tolerance analysis on the matching error were studied. The research results show that the camera MTF is the most important factor affecting the three-dimensional positioning error of the system among various factors affecting the measurement error of the optical imaging system for three-dimensional measuring instrument.When the MTF_N value of system is greater than 0.4 lp/mm and the geometric distortion of the system is less than 1 pixel, the PSF energy is concentrated in the ring with a radius of 3 μm(less than 1 pixel) and the PSF peak reaches 0.9, the positioning error of the 3D instrument can reach the second-order accuracy.