Concerning the single function of single watermark algorithm, a multi-purpose watermarking algorithm for color image combined with Discrete Wavelet Transform (DWT) and Quaternion Discrete Cosine Transform (QDCT) was proposed. Firstly, the DWT was applied to the three scrambled channels of a color image, and QDCT was applied to their low frequency subbands and medium frequency subbands, then some of the real coefficients were used to construct a coefficient matrix, and the robust watermark was embedded into the singular value of it by adding principle. Secondly, the image was divided into 2×2 sub-blocks and preprocessed with QDCT. The characteristic fragile watermark was generated by the low frequency modulus coefficients of QDCT and embedded into the Least Significant Bits (LSB) of the space domain. The experimental results show that the robust watermark has good robustness against JPEG compression, noise, contrast adjustment, cropping, rotating and hybrid attacks, and the fragile watermark is sensitive to tampering and has accurate tamper localization.