The bed temperature characteristics of CFB boiler mainly refer to consciously adjusting a specific influencing factor on the premise that other influencing factors remain unchanged. The increase and decrease process of this factor will bring about the relevant change law of the overall bed temperature and its local distribution. The corresponding relationship between the univariate regulation and the bed temperature change is called the bed temperature characteristic of CFB boiler. In order to understand the temperature distribution in the circulating fluidized bed combustion chamber, it is necessary to understand that the temperature distribution is the result of heat balance along the height. The internal heat source of each part is determined by the distribution of fuel combustion share. The distribution of combustion share depends on the combustion characteristics and particle size characteristics of fuel; The heat absorption source of each section is the heating surface, and its heat transfer coefficient depends on the local substance concentration and temperature; The heat exchange between sections depends on the mass and gas exchange between sections. It should be noted that there is a strong mass exchange along the height direction of the combustion chamber, which is called longitudinal particle mixing.