Using the data of Doppler radar from May to September, 2004 to 2008 and automatic station data in Dalian, by means of the echo typing, optimal Z I relation, system error elimination techniques, the overall localized Z I relation is obtained, which is applicable to operational observation. Taking five heavy rain events in Dalian in 2008 as examples, application experiments are conducted. The results indicate that there is a substantial increase(more than 40%) in the accuracy of precipitation estimate of RPG precipitation estimate products, compared with the default estimate value from WSR 88D. The application from 2009 to 2011 shows that the accuracy of the estimate values is up to more than 75% steadily.