In view of some shortcomings existing in the surface acoustic wave gas sensor composed of the single input output and the double input output transducers,a type of wireless and passive gas sensor that can also measure temperature was studied.The sensor was designed by applying the transition energy principle of inter digital transducers to set up a rational layout of inter digital transducers and reflectors based on the surface acoustic wave delay line theory,and taking the three reflectors as reflecting reference each other.The proposed scheme can reduce the effect of the interior signals of sensor and the environment temperature on the signal measurement,and enhance the sensor sensitivity and measurement accuracy.The sensor has characteristics such as simple structure,wireless and passive,suitable for working in complex engineering environment unsuited for contacting.