In a method for an apparatus correcting image distortion in diffusion-weighted echo-planar magnetic resonance imaging, a marker sequence is applied before a diffusion-weighted echo planar imaging sequence, to form a combined sequence. The combined sequence is used to obtain marked images with different preset b values and different preset diffusion directions. The diffusion-weighted echo planar imaging sequence is used to obtain diffusion-weighted echo planar images with the same b values and diffusion directions as the marked images. A stretching coefficient and a displacement coefficient are calculated for each image data column of the diffusion-weighted echo planar image. The stretching coefficient and displacement coefficient are used to correct the diffusion-weighted echo planar images.