An indoor incubation experiment was conducted to investigate dynamics of available phosphorus (P) content in paddy soils different in soil moisture regime (submerged or 60% water holding capacity) and submerging water layer as influenced by phosphate fertilizer application. The results indicated that soil available P content was obviously increased with the phosphate fertilizer application rate. The enriching point of available P depended on soil types, being P₂O₅ 60~120 mg/kg in the paddy soil derived from Tertiary red sandstone, and P₂O₅ 120~180 mg/kg in the paddy soils from Quaternary red clay and loess-like lake sediment. Soluble P was mainly distributed in soil solution and less in the water layer. However, a higher concentration of soluble P was found in the water layer of submerged paddy soils with excessive P addition (>P₂O₅ 180 mg/kg). Thus, P loss is likely to occur under unsuitable water management.