According to related data and investigation after the disaster,we analyzed the background,process and situation of the disaster caused by extra rainstorm in July 14.It is concluded that landform and earth's surface structure in Fufeng county are useful to the formation and occurrence of strong convective weather in some areas,sustaining drought in the former period cumulated energy for the disaster,direct reasons causing the disaster are warm-moist air flow from southwest,cool whirlpool in high altitude and cold front passing Fufeng county in July 13 and 14,enhancement of dynamic of plateau form slope and the location of the county seat are important reasons causing county seat being center area of the rainstorm.The important factors causing the disaster also include that urban space is narrow and small,social economy is highly intensive in urban region,drainage system is jammed seriously and the thought preventing natural disaster pay more attention to fight droughts and look down upon flood disaster.Therefore,it should be on guard that catastrophe occurs in small region.The research and prevention of small region disaster should be intensified.