PDF417 is one of the widely used twodimensional barcodes, and the detection and location of its barcode area becomes a critical issue in the recognition process. While the location technique under the complicated background is far more than perfect now.We study this problem in this paper. Based on this, an algorithm based on mathematical morphology operations and the Canny marginal detection is proposed, afterwards, some local precise work is done to achieve the accurate location of the barcode area. The experimental results show that the method can effectively recognize the PDF417 barcode under various complex backgrounds, such as low contradistinction, blurred edges, incline and logo interference.