Abstract: The dynamics of soil available phosphorus(SAP)and total phosphorus(STP)in spring wheat field after two years of regulated deficit irrigation(RDI) were studied in Hexi oasis irrigable region.The differences in soil phosphorus indexes at harvest between two experimental years were analyzed using Paired-Samples T Test (2-tailed),and the relationships between SAP,STP and the total irrigation water amount(IR) throughout wheat growing seasons,and between SAP and STP were also regressed. Results show that the soil phosphorus nutrients in spring wheat field are significantly affected by RDI, and the STP and SAP in 0～20cm and 0～40cm layers are positively linearly correlated with IR during wheat growing season, while SAP is linearly increased with STP increase. The relationships between SAP, STP and IR, and between SAP and STP in 0～20cm are similar to those in 0～40cm layers.