The spectra of terminal products from five general high explosives are studied by using detonation spectrum technique developed by the authors. The results show that H2O increases with negative oxygen balance increasing. The CO2 increases with the increasing of carbon content in the explosive, and C2 raises too. It provides some useful data for selection donor explosive used to synthesize diamond by detonation product method. Comparing the measured data with ealculating values from BKW equation, the results are similar. It shows that the monochrometer technique is an effective, economic and convenient method for study microscopic mechanism of explosive fast reaction.