The purpose is to understand how indoor air pollution affects people's health. Methods: The survey was conducted in a community in Wancheng District, Dongguan on February, 2007. A number of air pollution indicators were monitored in 50 apartments with different decoration conditions and living time of less than half a year. 120 residents living in 50 apartments were interviewed face to face. At the end of the investigation, carbon monoxide, carbon dioxide, formaldehyde, benzene, toluene, ethylbenzene and xylene exceeded the standard by 65438 000%, 65438 0200% and 290% respectively. /kloc-80 out of 20 residents reported physical symptoms. It is concluded that formaldehyde is the most serious indoor air pollutant, and indoor air pollution directly harms residents' health.