Recently research shows that heterogeneous model is needed to explain some complex combustion behaviors in SHS. However, more heterogeneous details be considered more difficulties will be faced. A micro-heterogeneous & macro-homogeneous model is proposed in this paper based on some previous works for this problem. Combustion compact is divided into lots of little units, which are composed of a large number of small particles. Considering a well-mixed situation, properties of every unit must be almost the same, so the compact can be treated as a macro-homogeneous system on the scale of these little units. During the combustion, every unit will have a heterogeneous properties and change; it can be gotten by a micro-heterogeneous model. Therefore, the micro-heterogeneous characters are connected with the Marco-combustion behaviors. Combustion dynamics of Ti-C-Fe system was studied to certify this model. Results show well consistency with experiments results.