In this paper we designed and made the sprayer, the water mist field characteristics produced by the sprayer were measured by the LDV/APV system. On the basis of the measurement, the experiment of extinguishing liquid fuel flame by the water mist was made. The temperature of the flame area was measured by thermocouples and infrared thermography before and after the application of water mist. The experimental results show that it is feasible to apply in water mist fire suppression, which has better characteristics.