Aiming at the problem of poor robustness of image watermarking algorithms when the attack is strong,a robust method based on graph-based transform (GBT),discrete wavelet transform (DWT) and singular value decomposition (SVD) is proposed.First,we perform non-overlapping block processing on the carrier image,select the sub-blocks with higher pixel variance values and perform DWT on each sub-block to obtain its low-frequency coefficient matrix,and then perform GBT and SVD on the low frequency coefficient matrix in turn to obtain the singular value matrix,and finally embed the watermark information to the largest singular value matrix.The experimental results show that when Pirate image structure similarity (SSIM) reaches 0.97 or more,the algorithm in this paper can effectively resist attacks such as noise,filtering,JPEG compression,cropping,and exchange of ranks,and the normalization coefficient (NC) value is all above 0.9.