DWI is widely used in MRI. Due to the application of diffusion encoding gradients and usage of EPI for signal sampling, diffusion images usually have two kinds of artifacts. The first kind is image sequence and system related artifacts, such as EPI artifacts and field inhomogeneity induced distortions. The second kind is subject related artifacts which come from either cardiac pulsation and respiration or bulk motion. Various methods have been developed to reduce the first kind artifacts, while bulk motion and low SNR are less addressed. This presentation will give a concise review about the artifacts and the correction.