Abstract: During the mining period,there is an unknown location of a small kiln fire area in the original Dahonggou Coal Mine.After years of governance,it is not completely extinguished.After the original Dahonggou Coal Mine is merged into the southern area of Wudong Coal Mine,it needs to carry out concealed fire sources detection of original Dahonggou protective coal pillars.Aiming at the large difficulty,large error and the problem of limitations of existing technologies in detecting concealed fire sources in the coal mine downhole,a technology based on laser flash method for detecting concealed fire sources in coal mines is proposed.The laser flash method is used to analyze the changes law in thermal diffusion coefficient,thermal conductivity,and specific heat capacity of coal and rock samples in the B₃₊₆ coal seam at different temperatures,so as to detect the dynamics of concealed fire sources in original Dahonggou flood protection channel coal pillars.According to hole drilling,coal samples from the B₃₊₆ coal seam and roof rock samples are collected,and the analysis of their thermal conductivity,thermal diffusion coefficient,and specific heat capacity experimental data is conducted,it is found that there are high-temperature areas around the hole bottom of boreholes 4^#,5^#,and 7^#,with all temperatures exceeding 130℃.