A algorithm using image edge detection operators to extract the edge of defaced barcode and to identify it was put forward to solve the problems of slow identification speed and low recognition rate. Sobel operator was applied to detect the barcode edge after analysis of the characteristics of existing commonly used edge detection operators. An improved Sobel operator was put forward, which increase two directions template, which can overcome the thicker lines and other defects of the original operator in image edge detection. The experiments showed that the new operator can quickly and efficiently identify defaced barcode; the correct rate is 98. 5% .