An image interpolation processing device is provided for interpolating at least one line between two adjacent lines. A prefetch unit is to prefetch pixel data of the two adjacent lines with a predetermined pixel length, so as to obtain a plurality of basic characteristics that are then stored in a first register. A characteristic processing unit is used for cutting and/or linking the basic characteristics to generate at least one set of linked characteristics. The linked characteristics are stored in a second register, as a reference for an operation unit to perform the interpolation. The operations between the operation unit and the prefetch unit are separated by a predetermined edge length.