A digital watermarking technology was put forward, which can enhance the robustness of digital watermarking system. This method encodes the watermark information as quick response code (QR Code) and embeds the QR code as a digital watermark into the intermediate frequency of the digital image by two discrete wavelet transform. This method increases the robustness under the premise of invisibility. Comparative experiment was carried out and the results showed that QR code as a digital watermark increases the security and robustness, and is applicable for any kind of watermarking algorithm.