• The environmental friendly fluorinated acrylate copolymers were designed and prepared successfully via a simple and economical route. • The preparation and modification process of ultrafine dry powder extinguishing agent were simple and easy to be controlled. • Sodium bicarbonate ultrafine dry powder extinguishing agent with excellent hydrophobic and oleophobic properties was successfully prepared. • Water/oil contact angles of fire extinguishing agent could reach up to 117° and 120.5°. • The flame of aviation kerosene was successfully extinguished without reignition. Common ultrafine powder fire extinguishing agent couldn't put out the oil fire. To solve this problem, a simple and controllable way for preparing hydrophobic and oleophobic fire extinguishing agent was developed. Firstly, fluorinated acrylate copolymers (FP) with different fluorine contents were prepared and used to modify the extinguishing agent. Unlike perfluorooctane sulphonate/ perfluorooctanoic acids (PFOS/PFOA) with C8-fluorocarbon chains widely used as modifiers, the prepared FP with C6-fluorocarbon chains not only met the environmental standards, but also possessed excellent properties. Subsequently, the fluorine contents of particles modified by two FP were 19.3% and 37.4% respectively. The contact angles of deionized water were 103.5° and 117° respectively, and those of aviation kerosene were 68° and 120.5° respectively. They possessed outstanding hydrophobicity, but particles modified by FP2 had better oleophobicity. Finally, the particles covered the surface of fuel, which prevented the fuel from evaporating. Combined with the effect of interrupting the combustion chain reaction, the flame was gradually extinguished. [Display omitted] [ABSTRACT FROM AUTHOR]