On August 3 and 4,1996,Typhoon 9608 made continuous great rainstorm and exceptional rainstorm in south area of Hebei province,and caused very serious economic and personal loss.In advance,I forecasted on the extensive consultation of National Meteorological Center at 16:00,August 1: the Typhoon 9608 which had landed in Fujian province would move to north;on August 3 and 4,the east area of China would continously locate in superposed area of three gravitational wave resonance and one depressed tidegenerating force′s resonance,at that time if the typhoon is in the east of 110°E,the daily maximum rainfall of hydrometric station would get more than 500mm on that day,and the one of national station would also 200-300mm.The fact accorded with this forecast.The analysis shows:in August 1-4,after this typhoon landed,there was a inverted trough in its north side continously,and a westerly trough moved to east in Eastern Asia.In August 3-4,on the pumping effect of continous depressed tidegenerating force′s resonance,the inverted trough and westerly trough quickened to merge,and cold air and warm air joined,it promoted potential instability energy strongly release and led to exceptional rainstrom.This successful forecast proved once more that the abnormal superposition of depressed tidegenerating force′s resonance combined with interal condition of atmosphere is really a effective way to forecast exceptional rainstorm.