Abstract: The Kalman Filter calibration method was tested by "973" project (Research on the Formation Mechanism and Prediction Theory of Severe Synoptic Disasters in China) field data—a rainfall case on June 22, 2002. The analysis of parameters impacting on the result which the Kalman Filter calibration method figures out is done. The result shows that the Kalman Filter calibration method can improve the accuracy of radar rainfall measurement well. With the increase of observing times, the value which the Kalman Filter calibration method figures out is more accurate