Based on the GMS-5 imagery and weather data,a severe convective storm on 9 August 1999 was analysed.The results show that (1)the brighter area in the moisture image is in the upper troposphere with higher moisture.It is one of the criteria in prediction of storm occurring area;(2)the coincidence of brighter area in moisture image with higher potential pseudo-equivalent temperature (θ_se) is an important physical factor in the occurence of a severe convective storm.