The distribution characteristics of satellite picture,radar echo,surface wind field and θ_se field were analyzed in order to in vestigate the very heavy rain occurred in the southwest of Hebei province in August 3～5，1996.The results show that meso-β and mesoγ cloud clusters in meso-αare able to result in not only the precipitation enchancing but also the bursting of severe precipitation.In addition,the wet neutral structure is beneficial to the emerging and strengthening of very heavy rain.