Abstract: A CPW feed dual band-rejection ultra-wideband antenna is achieved by cutting slots of different shape and size on ultra-wideband printed monopole antenna. The relationship between structural parameters of slot and band-rejection characteristic is discussed though simulation and experiment in this paper. The simulated and measured results have shown that the antenna has wideband characteristc from 3. 1 to 10. 6GHz and good band-rejection characteristic from 3. 44 to 3. 77GHz and from 4. 91 to 5. 73GHz,which can avoid interference between the UWB system and WiMAX and WLAN. Beside, the antenna has good omnidirectional radiation characteristic on non band-rejection band. In addiation,through the detailed a nalysis of antenna surface current distribution,the equivalent circuit of antenna is deduced.