In this paper, a novel dynamic color image watermarking based on discrete wavelet transform (DWT) and singular value decomposition (SVD) is proposed. The watermark is embedded in different random block in every execution. This random movement minimizes more the risk of detecting the watermark and makes it difficult to find and to destroy. The encrypted binary watermark is embedded by modifying the singular values of a dynamic block generated randomly using a pseudo random generator from the sub-band LL after applying the DWT on the original image. This method respects the Human visual system (HVS) since the scaling factor used is adaptive to the image features in order to achieve the tradeoff between robustness and visual quality of the watermarked image. It is a semi-blind scheme because some of the original data are used for extraction. The experimental results show a good visual quality for the watermarked images and high robustness against several attacks avoiding at the same time the false positive error known by most of the SVD schemes and ensuring more security the authors.