This paper was an attempt to investigate the possibility of estimating qualitatively or quantitatively the impact sensitivity of melt cast explosives by thermal explosion theory. With the formulations deduced from thermal explosion theory to calculate the critical initiation conditions of explosive such as temperature and size of hot-spots,the critical initiation parameters of TNT, Comp.B and EAKR intermolecular explosives were calculated,and the calculation results were in good agreement with the experimental impact sensitivity data obtained experimentally from 10 kg hammer and 400 kg heavier hammer impact tests respectively.