Abstract: A kind of abnormal UWB monopole antenna is optimized by the Finite Differences Time Domain method combined with the genetic algorithm in this paper.According to optimal result,a compact planar antenna is made and carried out actual measurement.During the course of designing,they are simulated through ANSOFT HFSS9.0.The results that are achieved by these kinds of methods are similar.The relative bandwidth of the antenna with input voltage standing wave ratio less than 2.5 exceeds 100%.Finally,the radiation property for antenna is analyzed in frequency domain.Results show that the change of the directional pattern of the antenna designed is not large in the required frequency band.