Abstract: In order to study the damage effect of the change of explosion distance on in-cabin explosion, the simulation model of cabin explosion was established by using the finite element analysis software. The deformation of the bulkhead and the pressure of shock wave were analyzed. The results show that when the blasting distance ratio is L₁/L₂>1, the deflection of the far bulkhead is always greater than that of the near bulkhead. When the detonation distance L₁ increases, the deflection of the far bulkhead increases linearly, and the deflection increment is about 11% of the explosion distance increment, but the deflection of the near bulkhead does not change significantly. The shock wave that reaches the far bulkhead for the first time after the explosion in the cabin is the superimposed wave formed by the interaction of the initial shock wave and the reflection shock wave from the near bulkhead and the rigid bulkhead.