Abstract: A micro-heterogeneous , non-equilibrium and multi-sub-processes coupled model was presented based onlot s of experimental result s. Numerical analysis was used to study the behaviors of the Ti-C-Fe system in SHS. Thecalculated result s show that the relative density of compact has a dual-effect on SHS combustion behaviors , an optimal value exit s in some system , and a larger particle size of reactant s will lead to a relative slow chemical reactionand low combustion temperature. The result s show good agreement with experiment s.