Abstract: In order to analyze the effect of the initial environmental pressure on the shock wave overpressure peak and the temperature of the thermobaric explosives, some implosion tests were carried out in the 2.6 m³ explosion tank under different qualities of the thermobaric explosives, studying experimentally the impact of the initial ambient pressure on the shock wave overpressure peak and the temperature of thermobaric explosives. Test results show that the largest peak overpressure attenuation rate of the shock wave can be generated at 5 km altitude, representing an obvious effect of the initial ambient pressure on the shock wave. Using the dimensionless parameters of Sachs' ratio law and the Hopkins-Brown formula, an overpressure correlation model was constructed for incidence shock wave to generalize the flat data to different altitudes. Further analysis results show that the peak explosion temperature is proportional to the explosive charge in same initial pressure, and it decreases with decreasing initial pressure. And the peak temperature decrease extent of the large charge shows more than that of the small charge. The results can provide a reference value for assessing the explosive power and temperature effect of thermobaric explosives in high or low pressure areas.