Abstract:In order to determine flammable, explosive, toxic and harmful gases, and to grasp the occurrence of pollution and its development and control effectively, there is a need for highly sensitive detecting method. The gas sensor is a core of the gas detecting system. The optical waveguide (OWG) sensor is an important branch of the sensor technology, and attracts considerable attention with its unique qualities. This paper introduces the principle and making method of optical waveguide sensor in the detection of toxic gases, and latest research results of the optical waveguide sensor that detecting harmful gases are reviewed.