A field plot experiment with five P application rates and 4 replications each was conducted on Percogenic paddy soil in the Taihu Lake Region(TLR)in the years of 2002 and 2003 to monitor the concentration and fractionation of dissolved phosphorus(DP)in leachate at different depth.Results indicate that fertilization increases the concentration of DP in leachate at 30cm in depth at the initial stage,has a little effect in leachate at 60cm,and no effect in leachate at 90cm.However, the concentrations of dissolved P in leachates at 60 and 90 cm were higher than 0.02 mg L^-1,which suggests that the leaching may contribute to water eutrophication.Dissolved organic phosphorus(DOP)dominated in the leachate at 90 cm during the entire rice growing season accounting for 56% ~100% of the dissolved phosphorus(DP)in all the treatments except the control on Jun 13.The concentration of DOP in the leachate did not increase along with the P application rates in this experiment,indicating that DOP comes mainly from dissolution of the existing soil organic P by leachate and/or from organic manure applied or with irrigation water.