Abstract: To investigate children's personal and indoor exposure to PM_2.5, an intensive field study of monitoring was conducted from November to December in 2011 in Tianjin. The results showed that mass concentrations of personal and indoor exposures of children to PM_2.5 were (129.3±66.6)μg/m³ and (114.0±61.7)μg/m³, respectively. The total mass concentrations of elements accounted for 19.4% and 17.1% of the total mass concentrations for personal and indoor PM_2.5, respectively. Linear regression analysis indicated that most of the elements in PM_2.5 of personal exposure positively correlated with those of indoor exposure. Spearman analysis showed that the mass concentration of PM_2.5 of personal exposure significantly correlated with the mass concentration of indoor PM_2.5. Enrichment factor (EF) analysis indicated high values of EF for Zn, Pb, Cu, Cr, Ni, Sn, As, Sb, Cd, Tl, Bi, W and Mo, showing that these elements were affected by anthropogenic sources. Principal component analysis showed that the sources of personal exposure to PM_2.5 for children consisted of five components:combined sources of coal and vehicle emission, oil-burning ash, industrial dust, construction dust, and soil dust; while the sources for indoor exposure to PM_2.5 could contain:combined source of coal and vehicle emission, oil-burning ash, soil dust, and construction dust.