Abstract: For testing coal bed stress,the corresponding relation between drillings temperature and coal bed stress was researched based on the fact that the change of coal bed stress cause the change of drillings temperature and through laboratory experiment.The experimental results showed that on the condition that coal bed stresses were different while other experimental conditions were same,drillings temperature rose as the increases of coal bed stress;there were linear relationships between maximum temperature of diamond bit,rising rate of temperature of diamond bit,the speed of drilling hole,temperature of coal dust and coal bed stress.