Effects of soil moisture contents and phosphorus(P) application rate on form of soil inorganic P in red paddy soil were investigated through pot and field experiments.Results show in terms of percen tage against the total P,in organic P of different forms were lined in a decreasing order of O-P > Fe-P > Al-P> Ca-P.In the pot expermient,with increasing days of rice growth or increasing soil moisture and Papplication rate,contents of Al-P,Fe-P and Ca-P decreased,but content of O-P increased,whereas,in the field experiment,the effect of soil moisture content was markedly observed only on Ca-P in the early and late rice growth periods and on O-P in the mid grwoth period,and nothing was on Al-P and Fe-P Compostion of soil in organic P was closed related with P application rate.In the pot experiment,the effect of soil moisture on soil inorganic P,regard less of form,was not as significant,while the effect of P application rate wassign ificantly positive on Al-P and Fe-P in the early rice growth periods,and on Ca-P in the mid growth period,but little on O-P and Ca-P in the late growth period.Furthermore,the effect of interaction between soil moisture and P application rate was distinct on the four forms of in organic P.