Abstract: Since 1950's Dailing Experimental Bureau of Forestry located in the North of Heilongjiang Province has started to transform its swamp land in large scale by the means of afforestation and 7600 hectare plantations have been established so for.After establishing plantations the ecological conditions of the swamp were greatly changed in many respects. In contrast to the prior to afforestation the moisture of soil in a depth of 0—30cm was decreased to 65.3—76.2% from the origional 330—606%;the maximum and the minimum temperature were increased by 7.5℃ and 2.4℃ respectively,and the temperature of soil in a depth of 5cm was also increased by 2.5℃ as well as the temperature beneath 20cm by 1.5℃. The status of soil nutrition was much improved with the reduce of organic matter accumulated on the ground to 28.8% from 31.6% and the increase of dissolvable substance,for instance,nitrogen by three times and potassium by five times. The improvment of environmental quality resulted in changes in some elements of the flora,more species of mesophytes occurred while hydrophilous species were reduced.It is much better for the development of forest in such environment than previously.