Abstract: A field piot experiment was conducted to study phosphorus move down by leaching and its relation to the concentration of Olsen-P in surface soil on two types of paddy soils (the permeable paddy soil in the Anzhen site and the waterlogged paddy soil in the Changshu site) in the Taihu Lake region. Commercial NPK compound fertilizer and single superphosphate fertilizer were applied to furnish 0, 30, 75, 150, 300 kg/hm2 applied P per season. The results showed that all the Dissolved P (DP) concentrations in leachate samples were much greater than the threshold of 0.02mg/L caused the eutrophication. Fertilizer P rate had an effect on P concentrations in the leachate. The dominant form of P in the Ieachate was the Particulate P (PP). The average value for PP/TP in the leachate from the various P treatments on the permeable paddy soil and the waterlogged paddy soil was 70.9% and 67.0%, respectively. Under the normal P application rate of 30 kg/hm2 each season, the P losses by leaching at 30cm depth in the Changshu site was 469.7g/hm2, and greater than 378.5g/hm2 in the Anzhen site. The change-point of phosphorus by leaching was 33.0 mg/kg in the permeable paddy, higher than in the waterlogged paddy soil (26.3 mg/kg). This difference was probably associated with the different contents of organic matter and soil clay particle of two paddy soils, and indicating that P loss by leaching in the waterlogged paddy soil would be easier than that in the permeable paddy soil.