Abstract: Phosphorus (P) is an essential element for the growth and development of crops. In order to ensure China’s food security and crop yields’ increase, it is very important to increase the utilization of P. In this study, three calcareous soils (such as fluvo-aquic soil in Zhengzhou, cinnamon soil in Zhoukou and aeolian sand soil in Changtu) were selected as the research objects. A 90-day indoor test of soil buried was conduct to investigate the effects of combined application of amino acids and monoammonium phosphate (NH₄H₂PO₄) on the improvement of phosphorus fertilizer utilization in the three soils. The results showed that: (1) Amino acids could increase the utilization rate of NH₄H₂PO₄ in all three soils. Compared with the single application of NH₄H₂PO₄, the utilization rate of NH₄H₂PO₄ from fluvo-aquic soil in Zhengzhou, cinnamon soil in Zhoukou and aeolian sandy soil in Changtu increased by 21.16%, 10.87% and 4.06%, respectively; (2) The addition of amino acids reduced the conversion of Ca₂-P to Ca₈-P or to other insoluble forms of phosphorus in soils. Through correlation and path analysis of the three soils, it was found that the dominated factor in soils was Ca₂-P, with a decision coefficient (P < 0.05) of 0.836 (fluvo-aquic soil in Zhengzhou), 0.946 (cinnamon soil in Zhoukou), and 0.712 (aeolian sandy soil in Changtu), respectively. Moreover, the main limiting factor of fluvo-aquic soil in Zhengzhou and cinnamon soil in Zhoukou was Ca₈-P, with a decision coefficient (P < 0.05) of −0.066 and −0.401, respectively. While the main limiting factors of aeolian sandy soil in Changtu were Ca₈-P and Fe-P, with a decision coefficient (P < 0.05) of −0.080 and −0.105; (3) The addition of amino acids could lower the pH of the three soils, which was beneficial to increase the utilization rate of phosphate fertilizer; (4) According to the redundancy analysis of available P and soil physical and chemical properties of the three soils treated by amino acids after 90 days, organic matter (SOM) and calcium carbonate (CaCO₃) were the main reasons, which were explained 36.5% and 25.6% of the total variation of available P (P < 0.05), respectively. In short, the amino acids could increase the utilization of phosphate fertilizer in the three calcareous soils. The main way was to inhibit the rapid conversion of Ca₂-P by reducing soil pH and CaCO₃. In the three calcareous soils, the differences in the role of amino acids were mainly by the differences in the contents of SOM and CaCO₃, showing increasing SOM and reducing CaCO₃ in the soils could decrease the fixation of P in soil thereby increase the utilization of P fertilizer.