Abstract: With the large-scale development of CFB boilers,the furnace cross-section has far exceeded the CFB reactor in the chemical industry.The lateral non-uniformity of boiler operating parameters,especially temperature,seriously affects the safety and efficient operation of boilers.Accordingly,a two-dimensional cell model is established for the combustion system of a 300 MW CFB boiler.The model divides the cross-section into three parallel cells.The model includes gas-solid fluidization model,lateral dispersion model,combustion model and heat transfer model.The calculation and test results show that the temperature distribution in the width direction is obvious non-uniform.The temperature of the intermediate circuit is higher than that of the sides.The dispersion coefficient of dilute region has a significant influence on the lateral temperature distribution. According to the model calculation and test data,the dispersion coefficient of dilute region should be in the range of 0.006-0.010 m~2/s.In the dense bed,the lateral dispersion of particles is severe.When the coal flowrate of each coal feeding point is changed,the local concentration of coal is quickly eliminated by lateral mixing and dispersion. Therefore,the lateral temperature distribution of the furnace is less affected by the change of coal feeding distribution.The key point for the temperature deviation is that the water wall area of each cell on sides is larger than that of the middle one.By adjusting the arrangement of the screen heating surface in the furnace,the problem of uneven temperature distribution can be effectively improved.