This paper used the idea of multiscale analysis to perform pre-filtering operation on the image with Repeated Rows. It turned the scalar wavelet into discrete multiwavelets transform and then selected the the low frequency subband. For the security of the watermark, the watermark logo is scrambled with a secret key. With the good performance of Quantization Index Modulus Modulation(QIMM), it embedded the watermark bit to different sub-bands and realized blind watermark extraction. Experiments showed that the algorithm in this paper had good image quality and robustness. It also increased the embedding capacity.