Aiming at realizing three-dimension reconstruction, both the high-precision calibration of the low-cost stereo-camera system and the assessment of the quantitative accuracy are accomplished. The self-calibration bundle adjustment model that can calculate the platform parameters between cameras and internal parameters of camera is deduced.Based on relative orientation of the stereo-camera,atheoretical model for accuracy evaluation of ration is established by taking advantage of total calibration parameters and its covariance matrix. A stereo-camera system is established by using low-cost web camera. The calibration and accuracy evaluation of ration of the proposed system is carried out.Experimental results show that simultaneous determination of internal parameters and platform parameters of stereo-camera can improve the calibration accuracy and the stability. Quantitative evaluation model of considering parameters relativity can reflect the calibration accuracy for the stereo-camera system robustly.