Abstract: In order to study the influence of different coal blending ratios and steam soot on the outlet temperature and temperature rise of the furnace, the Shenhua No. 2 coal (high alkali coal) in the Dananhu area of Xinjiang Hami and the Baoli coal (low alkali coal) in the Balikun area were selected as the object of the study, to measure the temperature of the furnace by two-color temperature measurement method, and calculate the contamination coefficient of each heating surface according to the change of smoke temperature and steam temperature of each heating surface of the boiler.The slagging condition of each heating surface was inferred from the variation law of contamination coefficient with time. The change of furnace outlet temperature, furnace area temperature and contamination coefficient of each heating surface before and after soot blowing were analyzed and compared. The results show that the blending ratio of Shenhua No.2 Mine coal should be controlled below 80% in case of the more serious of slagging in furnace. The best blending scheme was that the boiler should put 5 coal mills into operation, of which A coal mill should be Baoli coal, and the remaining coal mill should be coal from Shenhua No. 2 mine. The study judges the feasibility of the blending scheme based on the slagging and slag balance characteristics before and after sootblowing, and provides guidance for the soot blowing frequency.