Water mist has a good three-dimensional cooling effect; however, its extinguishing effect on oil fires is less than that of foam extinguishing agents. This study aimed to enhance the gasoline fire extinguishing efficiency of water mist by adding KBr, Tween-80, and a dissolved CO2 solution as multicomponent additives with different suppression mechanisms. The fire extinguishing time was measured to evaluate the extinguishing efficiency of different additives. The test showed that KBr mainly works near the flame base and makes an unstable gap between the flame base and the gasoline surface; the Tween-80 mist and dissolved CO2 mist make the flame height lower under the test conditions. By analyzing the different extinguishing phenomena, temperature and efficiency of each additive, the multicomponent additives were proposed to enhance the extinguishing efficiency based on different mechanisms. The results showed the water mist with KBr, Tween-80 and dissolved CO2 resulted in a remarkable improvement in the ability to extinguish a gasoline fire compared with pure water mist. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.