Abstract: The measurement of the soil dielectric properties is very important for researching the soil character and soil moisture. In the ground test of microwave remote sensing, the measurement of soil dielectric properties is the indispensable part. The soil microwave radiation interference data of different soil moisture content was measured successfully by using C band microwave radiometer. On the basis of interference principle analysis, a calculation method of soil dielectric constant was proposed by using the soil microwave radiation interference data. The soil dielectric constant accounted by means of interference method was very similar to the result computed by DOBSON model. In the process of the soil microwave radiation field trials, the interference measuring method can be taken as an optional method to measure the soil dielectric constant.