This paper proposes a band-notched reconfigurable ultra-wideband antenna based on square ring slot. By adding two ellipatical patches around the 3x3 circular metasurface, the working bandwidth of the antenna is effectively expanded. Through arranging two sets of square ring slots on the rectangular ground plane, notched band within the ultra-wideband is emerged. Furthermore, adjusting the on-off state of the eight PIN diodes in the square ring slot, the antenna realizes reconfigurable notched band. The results show that the -10 dB bandwidth of the antenna ranges from 3.5 GHz to 8 GHz, and five band-notched modes are realized at 3.5 GHz, 4.7 GHz, 5.1 GHz, 6.2 GHz and 7.2 GHz.