Abstract: The microwave integrated downconverter used in unify Carrier for c band is specially designed for satellite communication earth station. It has three channels. Features of each channel are as follows the net gain about 20dB, the NF less than 8dB, the interfering signal output level is less the 12MV for the prime-amplifier, the root-mean-squaz of flat-phase difference between each two channel is less than 0.3 degree, the insulation among three channels is more than 60dB, and the increment of gain amony three channels is less than ±0.5dB. The downconverter can track and telemeter up to twenty-seven frequency signals by means of chosing a correct local cscillating frequency.