In this paper,a double watermarking based integrity authentication algorithm is proposed to prevent watermark being embedded repeatedly.The aim is to solve the problem that fragile watermarking cannot prove the existence of itself,and prevent the tampering repudiation behavior by tampering the watermarked data first and then embedding the same watermarking information again.The pre-detection mechanism of robust watermarking is performed before the watermarking is embedded,so that any kind of watermarking cannot be embedded if the robust watermarking is already detected in the carrier data.Otherwise,the carrier data was divided into two parts according to the data features,namely the feature region and the non-feature region.The feature region is used to embed robust watermarking and generate the fragile watermarking,which will be embedded into the non-feature region.During the watermarking detection,the existence of the robust watermarking is detected at first.If there is no the robust watermarking,it shows the watermarking is destroyed and the data is incomplete.Otherwise,the integrity of the fragile watermarking will be detected.The integrity of the data will be further determined by the detecting result of fragile watermarking.The experimental results show that the proposed algorithm is able to prevent the watermarking being embedded repeatedly and has good performance for the integrity certification.