Abstract: Objectives To understand the status of air pollution and the source of particulate matters in newly decorated indoor places in Zhongshan city, and to provide basis for the prevention and control of indoor air pollution.Methods Indoor and outdoor PM_2.5 and PM₁₀, indoor formaldehyde, benzene, toluene, xylene and total volatile organic compounds (TVOC)in 35 newly decorated places were examined and analyzed.Results The average concentration of PM_2.5 and PM₁₀ in newly decorated indoor places were higher in outdoor air than that of indoor air.The indoor concentrations of formaldehyde,benzene,toluene,xylene and TVOC were 0.103±0.110,0.013±0.002,0.051±0.126,0.054±0.142,0.082±0.134 mg/m³,respectively.The indoor/outdoor ratio (I/O)of PM_2.5 was 0.996 (0.307-1.769), and that of PM₁₀was 0.941 (0.355-2.182). There was a positive correlation between indoor PM_2.5 and PM₁₀(r=0.933, P=0.000)and that between outdoor PM_2.5 and PM₁₀(r=0.988,P=0.000).Conclusions The air pollution in newly decorated indoor places was severe in Zhongshan city. The indoor air pollution of PM_2.5 and PM₁₀ in newly decorated places was caused mainly by the increase of outdoor particle matters.