Abstract: A small double notch ultra-wideband antenna is given in this design.The antenna uses a layered load slit，reducing the size of the antenna structure.The structure and size of the antenna are analyzed and optimized by using microwave simulation software HFSS，meantime，studied the return loss， voltage standing wave ratio(VSWR) and radiation pattern.The simulated and analytic results show return loss of the antenna less than-10 dB in the non-notch band，a stable radiation pattern，and an average of 7 dB return loss increases at 3.3～3.8 GHz and 5.0～5.9 GHz notch band，resulting in a very good notch inhibition，avoiding system signals mutual interference in the overlapping band and increasing system performance of the antenna.