Abstract: Combining with the characteristics of effervescent atomization and knapsack water mist fire fighting equipment, a water mist fire extinguishing equipment was developed. A series of wood crib fire suppression experiments were performed using the equipment. According to the process of putting out, the dominant mechanism of extinguishment with water mist was analyzed. A wood crib fire under 0.6A can be put out in 150 seconds. For 0.8A wood crib fire, it cannot succeed by effervescent atomization water mist equipment.