A combined method of pot culture under net with lab analysis was used in studying effect of sources of P on biological activity in crop rhizosphere in calcareous soil. The results show significant differences between treatments of different P sources,in population of microorganisms in soils inside and outside the crop rhizosphere and rhizosphere effect (R/B) during wheat growth period, with a decreasing sequence of K₂HPO₄ > CaMg-P > SSP > FA > CK. The population of microorganisms peaked at the later stage of the wheat growth. The activity of phosphatase in the crop rhizosphere increased with the crop growth, but varied from treatment to treatment in the decreasing order of FA > SSP > K₂HPO₄ > CaMg-P > CK. The activity of alkaline phosphatase was remarkably higher than that of neutral one.