There is provided an image interpolation method and an image interpolation apparatus. The image interpolation method comprising: interpolating pixels of a source image with zeros to form an up-sampling image; obtaining a reference interpolation kernel using the up-sampling image; and convolving the pixels of the source image, the reference interpolation kernel and a directional shift coefficient matrix to perform reference kernel interpolation based on directional shift on the source image. According to the image interpolation method and the image interpolation apparatus, based on the inclined bi-cubic interpolation, a directional shift matrix is introduced to remain the reference interpolation kernel unchanged while transforming the shift convolution matrix based on the direction, which is advantageous to optimize the interpolated image in various directions, such that continuity of the image content is considered and distortion is avoided at high frequency parts such as the edges or detail parts of the image.