Abstract: Many epidemiological studies have shown that specific element components in PM_2.5 are associated with increased cardiovascular and respiratory morbidity and mortality. At present, most studies used the element concentrations of the outdoor fixed station to represent individual exposure. However, due to the difference in indoor sources of elements in PM_2.5 and individual activity patterns, there is a certain deviation in replacing personal element concentrations with them from outdoor environmental station. This paper reviewed the relationship between outdoor and personal concentrations of elements in PM_2.5 and their influencing factors. It may provide a basis for more accurate assessment of the personal exposure concentration of elements in PM_2.5 and for the health risk assessment of elements in PM_2.5.