Abstract: Aiming at the problem that the thermal deviation characteristics of high temperature heating surface in high parameter circulating fluidized bed（CFB） boiler directly affect the safe operation, according to the mathematical model and heat absorption model of the complex flow network system established by the platen superheater in the furnace of supercritical CFB boiler, the characteristics of pressure drop, flow distribution, outlet steam temperature distribution, wall temperature distribution along the working medium flow direction and the heat absorption distribution were calculated and analyzed for the 600 MW supercritical CFB boiler under full load and 100 MW operating conditions.Results show that the flow deviations are 12.71% and 13.96% respectively, and the exit steam temperature deviations of the full screen are 33 K and 58.4 K in 600 MW and 100 MW loads, which are all within a safe range. The maximum outer wall temperature in 600 MW load is 616.5 ℃, which is within the allowable range of materials. The heat absorption distribution tends low near the side water wall and the furnace center line, and high at the middle of the heating surface.