In this paper, we propose a removable logo watermarking technique for copyright protection of digital image. Then, visible logo is inserted into digital image to protect copyright, and the information removed by the logo is embedded by a new quantization watermarking. In a legal usage, the image can be reconstructed without logo after watermarking detection process. Experiment results show that the proposed method maintains high image quality in both watermarked images and reconstructed images, and is practical and effective in protection of image copyright.