Microwave emissions at various frequencies are known to contain information on atmospheric chemistry. Information about water vapor is of great interest at 183.31GHz. Interferometric synthetic aperture radiometer avoids the disadvantages of manufacturing and carrying large antennas at the expense of complexity. This paper has discussed the design of the 183.31GHz interferometer system with two elements based on imaging theory and retrieving algorithm of two-dimensional synthetic aperture radiometer. And then several important experimental results are presented.