The invention relates to a waveform generator and the related method thereof for generating a second image data according to a first image data, wherein the first image data and the second image data correspond to different signal formats. The waveform generator includes: a first memory unit, a second memory unit, and an integrating unit. The first memory unit stores a plurality of scan line patterns. The second memory unit stores at least one first scan line data of the first image data, where each first scan line data corresponds to a scan line. The integrating unit is coupled to the first and the second memory units and generates each second scan line data of the second image data according to the plurality of scan line patterns or each first scan line data of the first image data.