In order to evaluate damage power of thermo-baric warhead, the oxygen consumption of one thermo-baric warhead was studied by static experiment. The real-time variety graph of oxygen concentration-time was obtained. The energy releasing efficiency and damage power were evaluated by duration of oxygen consumption and quantity. Results show that the energy releasing efficiency and damage power of thermo-baric warhead are 1.13 and 1.55 times higher than that of plastic bonded explosive warhead, respectively. The assessment results are consistent with those evaluated using parameters of by shock wave and temperature.