Abstract: We analyze the mechanism of flame propagation in the gap and the effects of the material thermal conductivity and thermal deformation temperature on the propagation of the flame in the gap; we study the effects of flame ablation on the detonation resistance of plastic flameproof surface from the aspects of heat absorption capacity, roughness change, gap change, explosive residue, etc. We expound the flame ablation test and several matters needing attention, and propose several conditions for simulating flame ablation test.