The characteristics of natural organic matter (NOM) released from a representative forest soil under acidic, neutral and basic conditions were investigated based on their physicochemical properties.It was found that as the releasing condition changed from acidic to basic, NOM components possessing higher UV absorbing capability, stronger fluorescence EEM intensity and larger molecular weight were released into water.On the other hand, the DOC concentration of NOM released under basic condition was tens of times larger than that under either acidic or neutral condition.