Abstract: In view of the shortage of existing test equipment for the migration characteristics of natural combustion temperature field of loose coal,according to the actual combustion characteristics of loose coal,the simulation experimental system of coal fire development and evolution was designed and developed independently.The coal samples of Mengcun Coal Mine in Xianyang,Shaanxi Province were selected as the research object,and the combustion process of loose coal was simulated by the device developed,and the distribution and depth movement of high temperature area during the combustion of loose coal were analyzed.The results show that in the process of loose coal combustion,the temperature scale of coal sample system increases first and then decreases with the increase of time,and the whole combustion chamber decreases to ambient temperature after 600 hours of test operation.The deep movement direction of the high temperature area shows a non linear law.During the test,the high temperature area of loose coal was concentrated in the middle and west parts of the coal fire development and evolution simulation experiment device,and the time of falling to the limit oxygen concentration (1%-3%) was similar to the ignition temperature.In the temperature drop stage,the key points of the high temperature region were the slowest among the measurement points of the same layer.During the test,the high temperature area of loose coal was concentrated in the middle and west parts of the coal fire development and evolution simulation experiment device.The temperature of the key point decreases in turn in the process of deep spreading.With the increase of depth,the time difference between the key ignition point temperature and the peak temperature increases exponentially in the high temperature region,and the growth rate decreases linearly after the key point temperature reaches the ignition temperature.The time range of the rapid decline of oxygen concentration at key points in high temperature region increases with the increase of depth.The research results can provide reference for the prevention and control of spontaneous combustion of loose coal such as coal piles,residual coal and coal storage.