A composition for low density, ultrathin, and inorganic films, comprising a mixture of 70-82% of calcium carbonate by weight, 10-15% of linear polyethylene by weight, 1-5% of stearic acid by weight, 0.40-0.80% of aluminate by weight, 0.20-0.80% of titanic acid ester by weight, 0.4-3.0% of modified polyethoxylated silicone emulsion by weight, 0.05-0.5% of foaming agent by weight, and 0.01-0.1% of foaming agent accelerator by weight. The inorganic of the present invention is reduced in thickness, light in weight, easy to degrade, high tensile and high tear strength, toxicity-free, high temperature resistance, and low prices, so as to fulfill the requirement of producing the mulch, trash bags, shopping bags, and package bags.