Abstract: The paper designed a kind of left-handed material with the structure of double triangles and resonance ring，and proved that material has properties of electromagnetic left-handed material by theoretical calculation and simulation experiment. It loaded the left-handed material with structure of double triangles and resonance ring on a rectangular microstrip patch antenna, gave structure parameters of the antenna, and compared performance of the antenna before and after loading the left-handed materials using HFSS simulation software. The simulation results show that the loading of the left-handed materials improves bandwidth of the antenna, increases gain of the antenna, and suppresses the sidelobes.