Abstract: In this paper,the effects of incinerator structure on combustion safety,temperature distribution,and flue properties were investigated with numerical simulation.The cold and hot states of a 650 t/d municipal solid waste incinerator were simulated.And the effects of secondary air temperature,secondary air layout,and rear arch angle on the combustion in the incinerator were explored.The simulation results showed that the overall average temperature in the furnace decreased by about 80℃,as the temperature of secondary air decreased from 180℃ to 25℃.The overall temperature decrease was beneficial to alleviate the problems of coking and high-temperature corrosion in the furnace.When the secondary air in the lower part of the front wall moved to the front arch,the secondary airflow formed an "air curtain" and pressed the combustible gas close to the grate,which may cause problems such as grate burning and tempering at the feed port.On this basis,when moving the front arch secondary air behind the front wall,the first flue gas had higher fullness and a more uniform temperature distribution.And the gas component concentration at the outlet of the first flue complied with China's national standard,GB 18485-2014,Domestic Waste Incineration Pollution Control Standard,making the incinerator suitable when burning high calorific value domestic waste.