The processes of melting,initiation and explosion of the sample of Alcontaining PETN are observed directly by a high speed photograph during impact, and the solid products of the sample after impact from the gas gun are studied by SEM analysis. The results show that the aluminum powder is oxidized and burns during detonation. After conducting the related numerical modeling by the DYTRAN code,the process of the hot spot formation in the sample around the aluminum grain is described theoretically.