By usingaerial photography and field investigation, the SO2 absorbability of 7 main tree species were evaluated at experiment forestry centre of NEFU in Harbin, with the methods of CITYgreen model based on Arcview software. The result indicate that the SO2 absorbability of Acer negundo is the best, every 100 trees of them can absorb 2.21kg SO2, the direct economic value is 51.31 Yuan; Betula platyphylla is in the next place, every 100 trees of them can absorb 1.89kg SO2, the direct economic value is 43.88 Yuan; the worst among the deciduous and broad leaves tree spec ies is Fra xinus mandshurica, every 100 trees of them can absorb 1.53kg SO2, the direct economic value is35.52Yuan; the ability of SO2 absorbability of needle-leaf tree species is widely under the broad-leaf tree species. the SO2 absorbability of Pinus sylvestris var. mongolica is the best in three needle- leaf tree species, every 100 trees of them can absorb 1.13kg SO2, thedirect economic value is 26.23 Yuan; the worst is Larix gmelinii, every 100 trees of them can absorb0.92kg SO2, the direct economic value is21.36 Yuan. The ability of tree absorbing SO2 increases along with its growing, but the increasing trend is not increasing. The best ability of tree absorbing SO2 is the period of the most 、 vigorous growth, and the absorbing ability decreases gradually.
