An indoor pollution prevention system includes a plurality of gas detection modules, one or more intelligent control-driving processing devices, one or more gas-exchange processing devices, one or more intake passages, and one or more discharge passages. The intake passage is connected to the gas-exchange processing device and has an intake opening for guiding the outdoor gas into an indoor space. The discharge passage is connected to the gas-exchange processing device and has a discharge opening for discharging the air pollution source to the outdoor space. The intelligent control-driving processing device controls the gas-exchange processing device to be enabled under a surveillance condition of the gas detection module, so that the air pollution source passes through the discharge passage, filtered and purified by a cleaning and filtration assembly, and is discharged to the outdoor space, thereby allowing the indoor space to have a clean air.