A data interpolation method is utilized for obtaining an interpolation data of an interpolation point in a destination data, and a data number of the destination data has a horizontal magnification factor and a vertical magnification factor compared to a data number of a source data. The data interpolation method includes obtaining an input data from the source data according to an interpolation position of the interpolation point corresponding to the destination data, the horizontal magnification factor, and the vertical magnification factor, wherein the input data includes a plurality of input pixel values corresponding to a plurality of pixels; performing at least one reordering and interpolation calculating process on the plurality of input pixel values to obtain a plurality of output pixel values; and selecting an output pixel value from the plurality of output pixel values and outputting the output pixel value as the interpolation data of the interpolation point.