A blind robust image watermarking algorithm against row shifting was proposed, which used district points to design a revision method for resistance against row shifting to estimate row shifting number and turn row shifting into cropping. Firstly, at the embedding end, an original image was split into non-overlapping blocks. Then, a watermark was inserted by adjusting the numerical value of pixels from four columns in each block. Secondly, at the detection end, the revision method for resistance against row shifting was imposed on the watermarked image suffering from attacks. Then, a watermark was blindly extracted through pixel value comparison and majority judgment rule. The proposed algorithm has good invisibility and can achieve blind extraction. Moreover, the proposed algorithm has strong robustness against row shifting, since it adopted the revision method for resistance against row shifting. Experimental results also show that the proposed algorithm has strong robustness against common signal processing like Gaussian low-pass filtering, cropping, salt&pepper noise adding and Gaussian noise adding.