Abstract: Silica paraffin molten system was used to simulate cast explosives heterogeneous system. The rheological property of heterogeneous system was researched by changing the content of silica in the system and the interaction between silica and paraffin. Changing the interaction between silica and paraffin is an effective way to improve the rheological property of heterogeneous system. A series of comb copolymers called SMAC were prepared with different grafting degrees of octadecylamine to styrene maleic anhydride. Both the grafting degree of octadecylamine to styrene maleic anhydride and mass fraction of SMAC in system were found to be the key parameters of controlling the rheological property of heterogeneous systems.