Abstract: Simulation and analysis were carried out on flow and temperature distribution of syngas in three sections and circles of a convective waste heat boiler for pressurized dry pulverized coal gasifier, in which the gas flow field was calculated by combining species transport equation with Realizable k-ε turbulence model, while the particle flow field by DPM model. The two-way coupling model was applied to analyze the interaction between gas and particles. Simultaneously, the temperature field was calculated by weighted-sum-of-gray-gases model and DO model, and the basic parameters of high-pressure gases were decided by comparison state method, pressure and species amendment method, and Hottel’s method. Result show that the velocity of syngas reduces gradually from top to bottom heating surface and from outer to inner annular space, and the velocity peak deviates along the height direction due to the action of baffle plates. High concentration of particles appears at the syngas inlet, the bottom of each section and in the area blocked by upper plate, where soot blowers are required. The heat-transfer coefficients of upper, middle and lower heating surface as well as the outer water wall are respectively 274 W/(m²·K), 243 W/(m²·K), 198 W/(m²·K) and 223 W/(m²·K).