With the good characteristics of high efficiency, energy saving and environmental protection, supercritical W-flame boiler can effectively solve the problems of clean and high efficiency combustion of poor-quality anthracite using for supercritical pressure boilers. In light of a 600MW supercritical W-shaped flame boiler, combustion models in fluent 6.3 were used to study the combustion law of poor-quality anthracite in the furnace, the effect of air distribution on the combustion process was analyzed. The results indicate that symmetrical air distribution can not form symmetrical flow field because of the structure effect of the nose of the furnace. The effect of the nose of the furnace can be effectively balanced by increasing the velocity on the front wall and there exists an optimal ratio of air distribution. In the central zone of the lower furnace, the temperature is high and the O2 concentration is low, which is beneficial to the ignition and combustion of pulverized coal. Because the pressure in the center of the furnace is higher than that near the side walls, the pulverized coal are forced to move towards the side walls, which can cause the sidewalls to be eroded by the flame and slagging. The study results have great significance for the optimization design and improving the efficiency of pulverized coal combustion of supercritical W-shaped flame boiler.