Abstract: This study presents a micro-electro-mechanical systems（MEMS）-based benzene gas sensor with WO₃ thin film,which incorporates WO₃ sensing layer and Pt electrodes（for heating and sensing）.The WO₃ is deposited by sputtering process and then annealed to increase the cavity to enhance its sensitivity.The Pt electrodes are electron-beam evaporated on the sensing layer.The proposed gas sensor is tested at different temperatures（200℃,250℃and 300℃） to investigate the relation between the benzene concentration and resistivity of the sensinglayer.