A series of CH3N5-Sr(NO3)2 propellants catalyzed by TMOs are synthesized. TMOs added into CH3N5-Sr(NO3)2 propellants decrease flame temperature, increase combustion stability and burning rate. The decomposition mechanism of CH3N5-Sr(NO3)2 propellants has been proposed. TMO influencing reaction pathway of propellant’s combustion is reflected not only in condensed phase but also in gas phase.