Watermark hopping technique is proposed in this paper. The watermark is expanded into several expansion channels, then the host image coefficients in transform domain are endowed with double meaning by substituting them with some watermark expansion values. During watermark extraction, the watermark is obtained by retrieval-expanding the watermarked host image coefficients. Thus, a virtual channel for watermark communication is built in the host image. Watermark direct-inverse-alternating expansion method is presented to eliminate the adjacent channel interference. Chaos sorting technique is applied to shuffle the watermark. Experimental results show that the proposed watermarking scheme provides good invisibility and robustness