Abstract: Neutron CT imaging plays an increasingly important role in various fields such as materials science and medicine. In neutron CT images, factors such as abnormal or inconsistent detector responses can cause numerous ring artifacts of varying sizes in the reconstructed images. Based on the analysis of the causes of ring artifacts in CT images, a projection domain preprocessing method was used to locate and filter abnormal values in the projection sinogram, thereby reducing the impact of abnormal values on the reconstructed images. The corrected projection sinogram was then used to reconstruct the image, resulting in a ring artifact-free reconstructed image. The experimental results showed that the proposed method could effectively reduce ring artifacts and improve the clarity and accuracy of neutron CT images, providing reliable image support for the application of neutron CT in various fields.