A study was conducted on the initial heat hazard in mines,focusing on the testing and analysis of the original rock temperature and thermal environment in deep mining areas.The results showed that the original rock temperatures in the -580 m,-650 m,and -730 m layers were 31 ℃,32.5 ℃,and 34.7 ℃ respectively,with an average geothermal gradient of 2.45 ℃/100 m in strata.The main heat sources in the working face were the surrounding rocks and electromechanical equipment,accounting for 46 % and 24 % respectively.A new idea was proposed to measure the distribution of underground heat sources and the degree of heat hazard using absolute and relative heat dissipation indexes based on the total and unit lengths of ventilation tunnels.This study can provide a reference for assessing heat hazards in similar mines and implementing subsequent cooling engineering measures.