This paper mainly aims at the detection and alarm of dangerous gases in the process of chemical production in order to prevent safety accidents and casualties. The main detection gases are hydrogen sulfide, sulfur dioxide, hydrogen, hydrogen chloride, phosgene, hydrogen fluoride, hydrogen cyanide, sulfur tetrafluoride, sulfur hexafluoride and so on. All the detectors and sensors of the company are imported from well-known foreign manufacturers with accurate detection and high sensitivity.