This article has been prepared to determine the effect of organic fertilizer on potential environmental risk of phosphorus in paddy soil.Dynamic change characteristics of Olsen P，CaCl2 P and TP content were analyzed by the method of waterlogged incubation with non sterilized and non sterilized comparative treatments.The results showed that the amounts of Olsen P，CaCl2 P increased with the amount of organic fertilizer applied.As expected，a highly significant positive correlation between TP content and Olsen P（r=0957**），TP content and CaCl2 P（r=0871**） were observed.After applying the manure，the effectiveness of phosphorus in paddy soil was improved，and the potential environmental risk of P was magnified.It was found that the peak of Olsen P，CaCl2 P and TP content were reached at 6~18 d，at the same time the desorbable capacity of soil P from soil to water were enhanced.The result that the mechanism of manure on potential environmental risk of P was due to the activation of organic acid and organic matter was related to the amount of manure.On the basis of comparative analysis，it was concluded that the organic acid was leading factor on potential environmental risk of P in paddy soil with the manure amount of 05% and 1%，and organic matter was major factor with manure amount of 25% and 5%.It was indicated that the effect proportion of organic acid and organic matter on potential environmental risk of P in paddy soil was 35%~50% and 50%~65%.