Abstract: To solve the problems of resisting to joint attacks and the low extraction accuracy rate that exist in present digital watermarking algorithms,a block fast fourier transtorm(FFT) based on digital watermarking algorithm was proposed.The algorithm normalized the image size and modified the values of blocked FFT coefficients according to the watermark.Watermark was embedded in accordance with the dual circulation.When extracting,the values of FFT coefficients indicated the watermark.Experimental results show that this algorithm can increase resistance to noise filtering and other conventional signal processing attacks;JPEG compression;rotation,translation and scaling attack;cropping and splicing attacks;and their combined attack.The bit error rate is almost 0.