Established the circular saw blade visual measurement system and developed geometry parameters measurement software. Calculated the inner and outer circle diameters and the roundness error, the tooth angle and the radial rake angle, the radial direction clearance angle on the basis of image processing. Calibrated the measured part using the standard gauge block. Improved the circle and the line sub-pixel methods. Experiment results showed that the fitting error of improved least–square linear fitting method was quarter of ordinary least–square linear fitting error under small difference of orientation time. The diameters of the inner circle and the outer circle ,the roundness error ,the tooth cusp angle and the radial rake angle, the radial direction clearance angle were respectively 25.204mm, 193.624mm, 0.005mm, 59.999°±0.00695°, 15.004°±0.0104°, 14.997°±0.0137° while taken sub-pixel method.