By using the DTA technique, the thermal decomposition of fuels (MEL,PVA,MC,AC) and thermal reactions of mixtures of these fuels and oxidants were investigated. The results show that MEL decomposed endothermally,PVA,AC,MC-exthothermally. The mixtures react more complicatedly. From the view of processing DTA data with the help of famous Kissinger method, some mixtures do not follow the conditions of Kissinger′s equation. The reason of such phenomena may be is that the gaseous products of thermal reaction do not influence the reaction process, in one hand, and the reaction happens in pure solid phase, in another hand. These phenomena are important for estimating the ignition ability of combustion and stability combustion of such gas generation compositions(GGC), The value of reaction constants of mixtures demonstrates the possibility and stability of ignition and combustion of mentioned mixtures. Because that MEL and its mixture with oxidants mentioned above decompose and react endothermally, MEL does not be used singly as fuel of pyrotechnic composition. MC,AC and PVA may be used as component of GGC.