A novel rectangleshaped antenna with dualband and pattern reconfigurable characteristics is presented in this paper. The antenna consists of a patchslotsquare loop structure and surrounding four QuasiHorn parasitic patches with Ushaped slot. By reconfiguring the depth of the side slot in the Ushaped slot, the antenna can cover two resonant frequencies of 5.25 GHz and 2.45 GHz, respectively. The main lobe of each pattern directs to one of four different directions in the plane with the elevation angle of 45° or 90° by controlling the states of one set of connections among the center patch, square loop and QuasiHorn parasitic elements. The antenna, which operates at two resonant frequencies within 2.42~2.52 GHz and 5.21~5.32 GHz, has a good performance of directional radiation properties, so that it has potential applications in wireless communication systems with multiple operating frequency bands and high performance against the interference.