Abstract: With the boiler capacity and steam parameters of circulating fluidized bed( CFB) greatly improved,material of high-temperature heating surface of the boiler has reached the highest level. In the actual operation,the steam temperature deviation characteristics of the high temperature heating surface tube panel are directly related to the safety and reliability of the unit. To accurately obtain steam temperature deviation characteristics of platen heating surface in a supercritical or ultra-supercritical CFB boiler,real furnace experiments were carried out on a 350 MW supercritical CFB boiler. By installing wall temperature monitoring points on all panels of two types of hightemperature platen heating surface of the boiler,steam temperature deviation and its distribution uniformity among tube panels in the same high-temperature platen heating surface were obtained under full boiler load condition,then the corresponding equipment transformation was carried out on the basis of the field test. The results show that there is an objective deviation of steam temperature among tube panels in the same high-temperature platen heating surface inside the furnace,and maximum deviation of steam temperature can reach above 60℃ . Wall temperature of tube panels laid with resistant refractory at wall side and facing fire side are obviously lower than that in central area,and maximum wall temperature deviation of high-temperature platen reheater is about 40 ℃ higher than that of high-temperature platen superheater. Maximum wall temperature deviation can not be monitored accurately by the traditional wall temperature monitoring points arranged alternately on the platen heating surface,and issue of relative inadequacy of wall temperature monitoring points arranged on tube panels of high-temperature platen reheater is more prominent. It is necessary to optimize the layout position according to platen width and height,especially more wall temperature monitoring points are arranged on tube panel facing the fire side( number from 4 th to 17 th inward to the outermost tube at fire side). The steam temperature deviation and its distribution uniformity of the platen type high temperature heating surface can be effectively controlled by the measures of split platen design and the optimization of the laying height of resistant refractory material. After optimization,the maximum steam temperature deviation of high-temperature platen superheater is 24 ℃( the maximum value of split platen superheater at water wall side is 16 ℃),and the steam temperature standard deviation is 6.2 ℃ . While steam temperature deviation of high-temperature platen reheater is 50 ℃,( that of split platen reheater at water wall side is 21 ℃),and the steam temperature standard deviation is 14.5 ℃ .