Simulation analysis of the vaporizing process in riser tubes of a boiler has been carried out on the basis of a processing method with considering nonuniform distribution parameters of radiative heat flow. Under condition of the nonuniform 3D distribution of furnace temperature

the radiative heat flow transferred to the surface of waterwall tubes is also nonuniform. For this reason

the waterwall surface has been divided into small simulation zones along directions of height and width of riser tubes

and the variation of the vaporizing process within the riser tubes along height direction has been analysed by using the abovementioned processing method. The results obtained are more reasonable compared with that obtained from the traditional lumped parameters method and the uniform radiative heat flow distribution method. By using the results obtained from the said processing method

occurrence of abnormal tubes with worsened heat transfer locality and back ward flow can be determined

having important significance for analysing safe and economic operation of boilers.