In the interaction of water mist and the flame,water droplets are involved into flame region mainly by momentum and water mist entrainment so as to suppress and extinguish fire.This paper investigated water mist entrainment and its influecing factors in the process of extinguishing the kerosene fire by water mist and proposed a method to calculate water mist entrainment quantity.The experimental results showed that the entrainment ability increases with the mist flux increasing,and decreases with the diameter of droplets increaseing.