Air flooding，as a creative EOR technique，is receiving more and more attention. The existence of explosion risk severely constrains the development and application of this technique. Thus，it is of great importance to obtain a clear knowledge and control of the explosion limits of combustible gases for fire warning and production safety of the air flooding technique. For this reason，the factors that influence the explosion limits of the combustible gases were analyzed，and the results show that：the components of the mix combustible gases can influence on its explosion limits，and the combustible gases with multi-component have an explosion limits which are the harmonic mean of those components；the explosion limits increase linearly with the raise of temperature，but increase logarithmically with the raise of pressure；the explosion limits decrease with the increasing volume fraction of inert gases，and different kinds of inert gases have various influences on explosion proof. The calculation models with different factors and unified prediction model of the explosion limits of the combustible gases were matched by using mechanism of numerical analysis and combination of empirical formula，and that will provide reference for predicting the explosion limits of oil-gas mixture under different conditions in air flooding technique.