According to the excessive error factors and difficult analysis of the binocular vision measurement systems, an error analysis method based on grey incidence technology was proposed. The grey attributes of the vision system were analyzed,and grey system theory and its correlation technologies were introduced into the error analysis of the vision measurement system. 9 factors or parameters such as lens distortion, centroid positional error, internal and external parameters in binocular vision system were all selected as independent variables, then sampled data were obtained for error analysis through experiments based on single factor variation. According to grey data processing method and grey incidence analysis technology, the influences of all error factors on final measurement accuracy were definited by irregular samples. Experimental results demonstrate the exactitude and validity that the grey theory is used for quantitatively analysis of errors for the vision system. Under grey theory significance, the incidence degrees of measurement errors with four kinds of factors,the radial distortion and tangential distortion of a lens, the included angle between two cameras and centroid positional error in feature points are larger than 0.859, which is higher than those of other factors.