1. A motion compensation interpolation device, comprising: an adaptive weighting unit, for receiving at least a frame that comprises a plurality of blocks, allocating an interpolation block in a predetermined number of blocks where the interpolation block comprises at least one target pixel to be interpolated, receiving a plurality of vectors corresponding to a plurality of adjacent blocks of the interpolation block, checking these vectors, and calculating a plurality of weighting values based on at least one vector that passes the check; and a blending unit, for receiving the corresponding pixel values of the vectors and generating the pixel value of the target pixel to be interpolated according to the weighting values and the pixel values.