1. A computer-implemented method for measuring form and position tolerances of an object, the method comprising: (a) receiving an image of a measured object and a preselected feature element to be fitted from the image stored in a storage device; (b) dividing the image of the measured object into a plurality of triangular grids, so as to obtain point clouds of the image of the measured object; (c) receiving a reference feature element selected from an image of a reference object corresponding to the measured object; (d) retrieving uppermost boundary points from the plurality of triangular grids; (e) fitting the retrieved uppermost boundary points to a feature element; (f) calculating form and position tolerances between the fitted feature element and the reference feature element; and (g) outputting an analysis report to show the form and position tolerances on a display device.