Abstract: Based on real-time data base of the Guangzhou Regional Meteorological Center and fine mesh precipitation NWP model from the Institute of Atmospheric Physics, Academia Sinica, a quasi-operational mesoscale numerical rainfall forecast system for the Pearl River Delta was set up on VAX 6220 and went through a 22-day long test from May 20 through June 10, 1990. Study of the result shows that the system is able to provide stable and timely products of forecast for 12 and 2-1 hrs. ahead, having some degree of reference value for short-term rainfall forecast.