Based on the research of the Fourier holographic technology,a digita l watermarking algorithm of color image combined with discrete wavelet transform and discrete cosine transform (DW T-DCT) transforms is proposed to make the robustness and invisibility of the watermark image better.Firstly,the watermark image is transformed by Fourier transforms and generated into the hologram image.Secondly,the B component of the vect or image in the RGB color space is decomposed by wavelet transform,and its low frequencies ae transformed by DCT.Finally,the hologram message was embed into the high frequency domain.The experimental results show that after the wat ermark image is embedded with strength of k=0.05,the peak signal to noise ratio (PSNR) reaches 47in the embedded image,and the watermark ca n resist those attacks of signal processing and cropping.At the same time,the similarity (NC value) of the extracted watermark and the original watermark can be maintained at more than 0.75,which indicates that the watermark has strong robustness and invisibility.This algorithm can resist cutting,filtering,noise and JPEG c ompression,and it can be used for copyright protection of digital images.