Using the Arbitrary Lagrangian-Eulerian (ALE) algorithm, the numerical simulation of the blasting warheads exploding in the air is realized. During the modeling process, the explosive was plotted with ALE elements, the shell with Lagrange elements and the air with Euler elements, the ALE meshes of the initial void were created in which the explosive products could flow, the meshes of explosive and the initial void were joined with common nodes, and the fluid-structure interaction was defined between the meshes of the explosive, shell and air. The diffusion of explosive products and the pressure distribution were obtained. The overpressure values at different distance to the explosion center were presented. The results show that the relative errors between the simulation results of overpressure and the experimental results at different distance to explosion center is less than 10%.