In this paper, by means of field measurement and fumigation experiments, it revealed that: the functional value of three factors that included total biomass, absorption intensity of SO 2 and absorption transformation periods of sulphur of leaves of different types of trees in Shenyang areas was the total potential, 4780 tons of purifying SO 2 by trees, which constituted about one twenty fifth of 120000 tons sulphur that released per year in Shenyang, and trees per square kilometre per year might purify ...