To improve the visual quality and embe dding rate of the existing rever sible image watermarking algorithm,a reversible image watermarking algorithm co mbining quadratic difference expansion and interpolation expansion is proposed. Firstly,the pixel points with grayscale values 0and 255in the original image are removed;then,the new image composed after removing the pixel points with g rayscale values 0and 255are divided into non overlapping blocks and each block is interpolated;the first half of scrambled watermark information is embedded in the image block generated by the interpolation expansion using the primary di fference expansion;finally, the remaining half of the watermark information is embedded into the previously generated watermarked image using the secondary dif ference expansion.Removing the extended pixel points and the pixel points with grayscale values 0and 255which have been removed before to generate the final watermarked image.The experimental results show that the algorithm both has a h igh embedding rate and a high visual quality (the average PSNR value is as high as 77.91dB),which can completely recover the original image.Compared with othe r reversible image watermarking algorithms based on difference expansion,this a lgorithm has certain advantages without having to consider the smoothness of the embedded image region.