A high gain microstrip antenna loaded with double layer metal square ring electromagnetic metamaterial radome is presented. The radome is located at 30 mm above the rectangular microstrip antenna, which fixes the spherical wavefront of the microstrip antenna radiation wave into the quasi plane wave front. The simulation results show that the antenna gain is increased by 2.5 dB. Meanwhile, the broadband frequency selection characteristics of the antenna cover reduce the Radar Cross Section (RCS) of the antenna.