Abstract: A new method to implement ultra-wide band planar magic-T in the paper was presented. The magic-T was composed of an ultra-wide band 90 degree phase shifter and an ultra-wide band 3dB 90 degree hybrid bridge. ADS software was used for circuit simulation and HFSS software was used for 3 D modeling,and the simulation results reached the design index. The central frequency of the new planar magic-T is 8.85 GHz,the bandwidth is 4.5 GHz ～ 13.2 GHz,and the relative bandwidth reaches 89%. The amplitude unbalance is less than 0.8 dB,the phase unbalance is less than 4 degrees,the voltage standing wave ratio is less than 1.4,the isolation is more than 20 dB,The size of magic-T is only 13 mm×5 mm×1.5 mm.