Abstract: This paper constructs a digital variable polarization monopulse detection system, which uses variety of emission polarization and virtual polarization synthesis receive mode, and obtains the fullpolarimetric HRRP and scattering entropy H and average scattering angle α by the ground target detection, provides the basis for reliable target detection and accurate recognition by combining HRRP and target polarimetric scattering characteristics, and illustrates that target scattering entropy can be used in the ground target detection in the digital variable polarization detection system.