CAD comparison is a technique to analyze the errors between a group of digitized points and its corresponding CAD model. It is increasingly more important in manufacturing as the optical digitizing devices have been widely accepted. We proposed a triangulation-based approach to deal with the CAD comparison problem; it can improve the computational efficiency tremendously for huge amount of measured points. The triangular facets were only an approximation of the original surface model, thus, several algorithms were proposed to enhance the accuracy of the error evaluation algorithm. Extensive experiments with industrial parts have been implemented to illustrate the characteristics of the proposed method. It has also been compared with commercial software to demonstrate its advantage over the available method.