There are some weaknesses for traditional microscope measurement, including small scope field, complex operation and subjective errors. To avoid these issues, a measurement system combining video and microscope is made. With the magnification of microscope and video, the accuracy of grating micrometer and the real-time notification of chamfer location, this system achieves high precise measurement. By displaying with two monitors, the computer can collect and display other measurement data while the chamfer is measured, which makes full use of the display resolution and enhances the efficiency of instruments. The method is valid for measuring size of special work-pieces.