Abstract: An adaptive digital watermarking scheme of double keys based on DWT is proposed to protect the copyright of digital image.The digital watermarking scheme extracts the content feature（watermark） from the original image with gradient segmentation threshold and inserts this content feature back into the image by modulating the wavelet coefficients.To enhance the robustness and invisibility of this scheme，the adaptive quantization step is calculated according to the local image characteristic.Due to more and more attacks on it，especially interpretation attack，in this paper，a kind of embedding and recovery method of watermarking is presented after analyzing the principle of attack.It includes double keys from attestation centre and author.This method can solve the interpretation attack and improve the watermarking security.The experiment results show that the embedded digital watermarking by the scheme is invisible and robust enough to watermarking attack，such as JPEG compression，noise，image cropping and median filter.