With GMS TBB data and the moist available energy method, an analysis of the nine hail fallout processes in Bameng area on 1998 is made. It suggests: (1) the temperature of cloud top and its horizontal gradient were important parameters for identification of hail cloud; (2) as hail cloud genesis there was a tongue of high energy at the low level and a center of low energy at the mid and upper level while a center of negative energy advection was located over its north and northwest.