Because that there are obvious differences of radiometric and geometric in SAR and optical image registration, this article presents a method based on cascade transform (CT) to register SAR and optical images. To remove radiation differences, gray transformation was used to extract stable structure information for the SAR and optical images. Then, Weighted-Logarithmic-Polar transformation is proposed to obtain scale and rotation parameters between the images, solving the global geometric differences. Finally, local geometric transform is conducted to get accurate matches and the image was registered by TPS model. The registration experiments show that the proposed method is able to extract stable structures and robust to the differences of radiometric and geometric. The precision of the registration method is high.