Based on theoretical model

the effect of unstable combustion heat release induced by unsteady combustion process

the most important source term of exciting on combustion stability and its triggering mechanism were analyzed and discussed. Then one dimensional premixed laminar flame model was separated into stable and unstable forms by the small perturbation analysis way

and the calculating method for heat release term in linear growth rate was built. With the distributions of temperature and heat release in space

the effects of varying initial temperature and specific heat ratio on this term were investigated. It is indicated that the combustion system using energetic propellants with low initial temperature always behaves more stably. For the same kind of propellant

increasing the specific ratio will make stability more sensitive to frequency

which will be more clearly for some frequency range.