Abstract: Because the gas at the end of a conical resonance tube can be heated to a higher temperature more quickly than at the end of a cylindrical resonance tube,researchers pay more attention to the conical resonance tube in the engineering field of the gas dynamic resonance ignition technique of liquid propellant rocket engine.By using Whitham rule,this paper analyzes the characteristics of pressure and temperature of the oscillating gas in the conical resonance tube theoretically and explains why the conical resonance tube can reach higher temperatures than the cylindrical resonance tube.Because the conical resonance tube can enhance shock waves,the gas at the end of the conical resonance tube has higher pressure oscillation amplitudes and higher temperatures and heating rates than that at the end of the cylindrical resonance tube.