With the development of wireless communication technology, miniaturized, multiband microstrip patch antenna has been widely used in wireless communication. In this paper, a hexagonal multiband microstrip antenna was designed with coaxial line feed and 120 degree slotting on the inside of each vertex of the hexagonal patch. Three different resonant modes could be effectively obtained by adjusting the geometry and size of the slotted patch, which could be applied to L-band and C-band. The simulation software CST was used to simulate and analyze this kind of antenna. The results show that the gain G≥6dbi and the return loss S11＜-10dB are all satisfied in the working band. The antenna has the characteristics of simple structure, small size and good gain, which can be applied to WiFi band in communication.