A multiple watermarking method combining a double random phase encryption system, frequency division multiplexing technology and quick response (QR) code is proposed. In order to enlarge the watermark capacity, an effective coding region of QR code is combined into a new image, and then the two composite images are used as real and imaginary parts respectively to form double QR code complex signals. The complex signal is encoded with random phase masks in the space domain and the spatial frequency domain into an encrypted watermark signal in form of complex noise. The double QR code encryption watermark signals are preprocessed and frequency division multiplexing is used to generate multiple watermark. The watermark signal is embedded redundantly in the medium-high frequency region of the residual components of the host image after Laplace decomposition. The watermark signals can be recovered without original host image, and the blind extraction can be achieved. Simulation results show that the proposed method is robust in scaling, filtering and rotation, and has a certain robustness for JPEG compression, cropping and Gaussian noise. The multiplexing capacity and the influence of random phase mask as a key on the quality of reconstructed watermark are also analyzed.