The invention discloses a CWT-QIM digital blind watermarking algorithm, which includes the embedding process and the extracting process of watermark. The embedding process of watermark includes the generation of watermark image, selection of an embedded area, DCT transform and vector quantization modulation-based embedding; the watermark extraction process is basically the inverse operation of thewatermark embedding process; the algorithm of the invention has excellent robustness and transparency, can effectively resist JPEG image compression, Gaussian noise, median filter, salt and pepper noise, scaling, rotation, cropping and other image attacks, improve the performance of digital watermarking algorithm, quantization and embedding watermark information, and can be extracted blindly without the original carrier image, can be easily and effectively applied to digital content authentication or digital copyright protection and other fields.