Based on the human visual system, a double image watermarking algorithm in wavelet domain was proposed. A piece of meaningful binary image was taken as watermark. On the basis of the original image analysis, the watermark was appended to appropriately selected parts. And double embedment of the watermark was performed through modifying low-frequency and high-frequency coefficients of the selected parts. It is shown that the image embedded watermark has better transparency, and two watermarks robustness complements each other. The algorithm is more robust for handling general images with JPEG compression and noise images.