The invention relates to the field of gas-sensitive film preparation, and particularly relates to a gas-sensitive film sensitive to ethanol and acetone and a preparing method thereof. The method includes firstly coating a substrate with a thermoplastic polymer nanometer fibrous suspension, drying the substrate to form a thermoplastic polymer film on the surface of the substrate, tearing off the thermoplastic polymer film from the substrate, preparing a nano-microcrystalline cellulose suspension through hydrolyzing cellulose with an acid, coating the thermoplastic polymer film with the nano-microcrystalline cellulose suspension, and drying the product to obtain the gas-sensitive film. Whether ethanol vapor or acetone vapor overflows or not can be determined through macroscopic morphologic changes of the prepared gas-sensitive film, and the prepared gas-sensitive film can response to ethanol vapor and acetone vapor.