Abstract: A new method for the monopulse track is introduced. By use of the sinusoidal spatial transform, the method transfers the nonlinearly variational characteristics on monopulse angle sensitive function versus scan angle in antenna array coordinate to a simple linearly shift one in sinusoidal space. While binding angle sensitive for 2 D phased array, it need binding only a curve in azimuth and elevation plane. Not only the access and storage spaces are reduced, but the quantization errors due to partition and beam controller are illuminated. The radar track precision is improved obviously.