An interpolation method, applied to image pictures, for interpolating at least one pixel into a position to be interpolated in a target image frame is disclosed. The interpolation method includes receiving a plurality of image fields having a corresponding image object, estimating a motion speed of the image object according to a distance between a first pixel position to which the image object located in a first image field of the plurality of image fields and a second pixel position to which the image object located in a second image field of the plurality of image fields, determining the pixel from the plurality of image fields according to the motion speed of the image object, and interpolating the pixel into the position to be interpolated in the target image frame.