To investigate the efficiency of water mist with additives on suppressing the typical pool fires including gasoline fire, diesel fire and transformer oil fire, a water mist generating system was employed to conduct a series of fire-extinguishing experiments. In this paper, the suppression effectiveness of the pure water mist was used to compare with the water mist containing additives, which comprises of KHCO3, carbamide, cocamidopropyl betaine and Capstone FS-1157. Meanwhile, the corresponding temperature characteristics and flame shape were measured and recorded. Results demonstrated that the fire-extinguishing performance of the water mist was improved significantly by containing additives. Wherein, the suppression efficiency of carbamide was higher than that of KHCO3 and surfactant because its decomposition reaction absorbed a large amount of heat, as a result, leading to reduction in the flame temperature. Also, the flame-retardant gases were generated and they can dilute oxygen concentration in the combustion region. However, the surfactant was better to be selected as the additive of water mist for the transformer oil fires in comparison with other additives. In contrast to the pure water mist, the average fire-extinguishing time was greatly reduced, particularly for the Capstone FS-1157. This is because the emulsification of surface-active agent plays a key role for heavy oil in the suppression process.