Abstract: This paper describes the performance of the 10-cm microwave radiometer developed in our laboratory, as well as the principle and the method for the measurement of ice thickness. This equipment was used to conduct experiments during the flight test in Liaodong Bay in 1986.The characteristics of the brightness temperature changes with the ice thickness and the distribution of the ice types on the flight-path have been obtained. The results of the test show that the radiometer is very effective for the measurement of ice thickness.