This paper puts forward a gas detector,which is based on spectral analysis technology,embedded technology,and Multi-spot measure technology.The gas detector reduces Random error and enhances measuring accuracy effectively.Firstly,the thesis dissertates the measuring principle of the gas detector,and introduces the manufacture flow of the gas sensor which is based on porphyrin molecule array.Secondly,the thesis introduces the gross structure design of the gas detector,and describes the optical measuring system,the gas flow system,the gauge head precision machinery transmission localization system,the embedded hardware control system and the date processing flow and the controlling system.Lastly,the thesis analyses the measuring error of the gas detector.