The invention discloses a method for optimizing a Parsytec on-line surface defect detection system. The method mainly comprises the following steps of: (1) maintaining hardware; (2) calibrating equipment; (3) grouping materials; (4) verifying defect; (5) establishing and optimizing a classifier; and (6) performing post-treatment. By the method, the Parsytec on-line surface defect detection system is optimized, so that the surface defect detection rate of the system can be increased to over 95 percent in a short time, the surface defect classification rate is increased to over 90 percent, and instantaneous, stable and accurate on-line surface defect detection and classification are realized.