Modern optical test technique, computer technique and photoelectric technique are combined. A test system with the CCD matrix, imaging objective and computer is researched to realize 2-D high accuracy, non-contact, real time and automatic measurement. The system has a simple structure and can be easily operated without the strict requests for environment. We need to obtain the edge contour parameter of the measured workpiece in order to achieve non-contact and automatic measurement. The testing device solves the key technologies of non-linearity smooth, the threshold value selection and edge abstraction. Because the system uses the method of the edge contour track to obtain the edge contour image of workpiece, the edge contour curve of workpiece can be precisely determined. Sphericity of micro glass bead is tested as an example. The testing system adopts non-contact test and overcomes some inherent disadvantages of the traditional testing method. The system will not cause permanent damage to the workpiece. The experiments show that the testing range is large, the absolute accuracy is less than 3 μm with good repeatability.