Increasing the availability of phosphorus in the soil is conducive to increasing crop yields and reducing waste of phosphate rock resources.In this experiment，the calcareous soil in Zhengzhou was taken as the research object.The effect of the combined application of γ-polyglutamic acid and monoammonium phosphate on the availability of soil phosphorus was investigated through an indoor buried soil test，and compared with the effects of oxalic acid and humic acid.The results showed that:(1)all three synergists with the same addition amount increased the utilization rate of phosphate fertilizer，and γ-polyglutamic acid had the best effect；(2)γ-polyglutamic acid significantly increased soil phosphorus effectiveness，when its mass ratio to monoammonium phosphate is 1∶1，the effective phosphorus content was increased by 57.85%；(3)γ-polyglutamic acid inhibited the rapid conversion of Ca2-P to Ca8-P and Ca10-P in soil.The correlation between soil available phosphorus and other phosphorus forms is Ca2-P(0.871)>Ca8-P(-0.797)> Ca10-P(-0.483)>Fe-P(-0.414)>O-P(0.347)>Al-P(-0.102)，path analysis showed that Ca2-P(0.759)was the main decision factor，Ca8-P(-0.087)and Ca10-P(-0.051)were the main limiting factors；(4)γ-polyglutamic acid can reduce the content of calcium carbonate in the soil and reduce the phosphorus adsorption sites in calcareous soil.γ-polyglutamic acid can improve the utilization rate of phosphate fertilizer.Under the condition of γ-polyglutamic acid and monoammonium phosphate，it can limit the rapid conversion of Ca2-P to inactive phosphorus and reduce the adsorption site of phosphorus.Glutamate is the main way to improve the availability of phosphorus in calcareous soil.