Abstract: The distribution of total P and Olsen P in loessial soil profile were studied using the 12 years long term fertilization experiments under rain fed and irrigation conditions(The National Monitoring Base of Soil Fertility and Fertilizer Efficiency of Loessial Soil). The result indicate that phosphorus from fertilizer mainly accumulated in plow layer of loessial soil, the contents of soil total and Olsen P in top 20cm soil layer as well as that in soil profile are increased greatly by fertilization; Under rainfed condition, soil total P and Olsen P of soil layer above 100cm were increased by applying phosphate or phosphate combined with organic manure. The Olsen P content of MNPK in 100—300cm soil profile were higher than that of CK, PK and NPK treatments, and the same trends also showed under irrigation condition. The total P and Olsen P contents of PK,MNPK treatments in 0—300cm soil profile were not only higher than that of CK and NPK, but also higher than that of same treatments under rainfed condition. Phosphorus losses by leaching do exist in lossial soil.