As a new technique applied to protecting the copy right of digital productions, the digital watermark technique has drawn extensive attentions.The watermark technique based on wavelet transform has been an active study field .In order to ensure the concealment and robustness of watermark, a blind image algorithm on the basis of wavelet transform was proposed.Firstly ,watermark was scrambled before the algorithm w as embedded .Then watermark information and spread spectrum sequence are modulated, and combining texture concealable characteristics of human vision system with just differenthating limit, were embedded into DWT domain of carrier image .Finally , making use of autocorrelation function characteristic of spread spectrum sequence ,watermark information was detected .In the detection process, it is not requisite for initial carrier image .The experiment results demonstrate that with the algorithm embedded watermark, watermark is no t easy to be found out .I t has a fine detected watermark effect .The algorithm is robust enough for JPEG degradation compression, clipping , noise attacks and low -pass filtering .