Abstract: For measuring the temperature of reservoir gas in the detonation driven shock tunnel (DDST) directly, argon is used as the driven gas with small amount of CF4 added as reagent to produce the temperature indicator C2 F4 based on a kinetic analysis of the thermal decomposition during the shock process. By using a high speed one-way valve connected directly to the shock tunneljust ahead of the entrance of the nozzle, a sarnpling system is constructed to sample the reservoir gas to a gas chromatography. The experimental results show that the sampling technique suggested here is available and the chemical temperature scale determined is convenient. The effects of condensation water on the wall of the driven section, as we use the oxyhydrogen detonation as the driven gas, are also discussed.