Relief materials are transported to the disaster areas after natural disasters. This paper studies the decision method of minimizing the shipping mass of relief materials under the premise condition of maximizing the number of victims supplied by relief materials. This paper gives the definitions of the substitution and collocation among relief materials, and presents a problem about minimizing the shipping mass of relief materials with formulation. Then, the paper establishes a two-stage integer programming model and studies the method to decompose the original problem into smaller sub-problems. Considering the uncertain quantities of relief materials, this paper designs simulation experiments in two different conditions. The simulation results show that the relief effects and efficiency are improved by describing relief materials structure.