Based on electromagnetic characteristic of metallic dendritic cell, negative permeability metamaterial composed of periodic arry of metallic dendritic cells is fabricated. A 2.64GHz microstrip antenna with dendritic structure is proposed. The results show that compared with the conventional microstrip antenna, the performance of the novel microstrip antenna with dendritic-structured negative permeability metamaterial has been improved remarkably. The 3-dB beam width of E-and H-plane can be reduced by 18°and 13°, respectively. The directional property of the antenna is enhanced, the gain is improved by 2.19dB and the efficiency is increased by 65%. It proves that the performance of the microstrip antenna is improved by using negative permeability metamaterial as the substrate.