Ring artifacts in computerized tomography (CT) images are introduced by the nonuniform response of the detector elements and the instabities of light source, which greatly influence three-dimensional reconstruction and quantitative analysis. A correction algorithm based on polar-coordinate transform and Fourier transform is proposed. Through polar coordinate transform, ring artifacts are transformed to line artifacts. Then, Fourier transform is applied to the line artifacts image. Furthermore, the frequency-domain filtering processing by a two-dimensional low-pass filter is taken. The corrected image is got by the inverse transform process of both Fourier and coordinates. Experiments are carried out by Matlab software, the result indicates that the proposed algorithm not only eliminates the ring artifacts effectively, but also keeps the image edges and increases the signal-to-noise ratio (SNR). In addition, the correction speed proves that it can be applied for batch processing.