The flame front,as an inside boundary,divides the fluid field into two parts,when its thickness is infinitely thin.According to conservation equations,characteristic equations and a turbulent combustion equation,parameters of the fluid field before and behind the flame front can be obtained.The structures of the fluid field in the tube at different time are got further by using Rubin-Lax-Werdroff scheme with boundary conditions at the ends of the tube and the flame front.Based on the reason above,dust explosion in a large-scale tube apparatus have been simulated mumerically and discussed in this paper.