From Doppler radar volume scan data, recording pluviometer data and automatic weather station data, using optimization technique and probability-fitting technique, we estimated quantitative precipitation in different climatic regions over the Huaihe valley. By comparing the two techniques and analyzing errors, we knew that the relative error resulting from probability-fitting technique was small. Particularly, the estimator value was uniformly smaller than the observational value in probability-fitting technique. For optimization technique, the estimator ability for over 50 mm per day was not strong. By calculating mean relative errors on different range segments, the optimal estimator region was from 110～200 km. Besides, the error was mostly due to Z-I
relationship's instability, precipitation echo's movement velocity and radar wave scan height's changing with different ranges. In addition, using rainfall data from nineteen automatic stations surrounding Hefei, we couducted comparative estimator experiment by Kalman filter adjustment technique, optimization technique and probability-fitting technique and got the conclusion that the Kalman filter adjustment technique is the best, followed by probability-fitting is better.