A stop band steep dual-notch ultra wide band antenna relates to an ultra wide band band-stop antenna of which the notch frequency band is located at the WLAN and WiMAX frequency bands, and is composed of a dielectric substrate (106), a radiation unit (101) formed on the dielectric substrate, an impedance matching input microstrip line (102) and a defected ground structure (DGS) (107). Two connected H-shaped grooves (103) are notched on the radiation unit (101) on the dielectric substrate, and the DGS is composed of T-shaped grooves (104) and square groove structures (105). The stop band steep dual-notch ultra wide band antenna of the present invention realizes the passband bandwidth required by the ultra wide band by utilizing the radiation unit, the impedance matching input microstrip line and a metal grounding plate, utilizes the circular radiation unit to improve the stop band attenuation inhibition, and utilizes the DGS and the groove structures on the radiation unit to realize the band-stop characteristic. The stop band of the antenna involved in the present invention is nearby 3.7 GHz and 5.75 GHz, thereby avoiding the mutual interference of a WLAN system and a WiMAX system.