Fengyun-3(FY-3) microwave humidity sounder antenna has the following specialties: high gain, low noise, high beam efficiency and high frequency. This Antenna has great influence on the precision of the whole system of FY-3MHS (microwave humidity sounder), offset parabolic antennae with conical corrugated horns are selected for these antennae. The frequencies of the antenna are 150 GHz and 183 GHz respectively (up to the highest frequency of the payload for the domestic satellite ), in addition, dual linear polarizations are also needed for the 150 GHz channels. Great challenges are brought about with the stringent demand for the FY-3MHS antenna. The analysis and design of this antenna need intercross knowledge of the electromagnetic theory, mechanics, manufacturing, measurements, quasi-optics, thermal and orbit etc. The successful design and assembly of FY-3MHS antennae fill up the gap of remote sensing in our country and stride a greatly leap in antenna theory.