A novel inorganic fine particle reinforced foam system for an oil-gas field and preparation method thereof. The reinforced foam system comprises a gas phase and a liquid phase; the gas phase is nitrogen, carbon dioxide or the air; the liquid phase is prepared from, by mass: 0.2-0.8 wt % of a foaming agent, 0.5-2.0 wt % of novel inorganic fine particles and balance of water; the novel inorganic fine particles are fine particulate matter with diameters being smaller than or equal to 2.5 microns captured and screened from the atmosphere.