The underground garage is a project with higher technical requirements and more complex processes. Making full use of the underground space to build a parking lot has achieved the purpose of diverting people and vehicles. Underground garages produce carbon monoxide gas, and because gasoline is not burned sufficiently, exhaust gas containing a lot of CO is produced. The underground car park is a closed environment, and the exhaust gas emitted is not easy to discharge, resulting in a choking smell in the car park, which is harmful to people's health. The project uses JB-TB-ASD5100 alarm controller and ASD5300C gas detector.