A system for detecting and cleaning air pollution in indoor space with heating, ventilation and air conditioning includes one or more outdoor gas detection devices, several indoor gas detection devices, several filtering devices, and a central controller. The central controller receives air pollution data detected by the gas detection devices, by connecting to a cloud device, performs an intelligent computation and comparison on the air pollution data to locate an air pollution location, and the cloud device transmits a control command intelligently and selectively to the central controller. Therefore, according to the control command, the central controller controls the air conditioning modulation mechanism of one or more HVAC components and enables the filtering devices to generate a directed air convection, thereby achieving the filtration of the air pollution to allow the indoor air pollution data to be a safety detection value.