Abstract: Objective To investigate the effect of different cocentr atio ns of calcium on the combining capacity of bile acid.Methods Different concentrations of calcium hydrogen phosphate solution were prepared and adjusted to pH=7.0.Then bile acid mixture chylomicron was added to the solutions dig ested at 37℃ in vitro.The contents of bile acid were measured in the supernatant and the sediment of different concentrations of calcium solut ion.Results Bile acid content was(2.72±0.27),(1.48±0.07),(0.64±0.04),(0.63±0.07),(0.76±0.09)Lmol in supernatant and(1.45±0.09),(2.56±0.18),(3.36±0.19),(3.21±0.28),(3.24±0.25)Lmol in sediment of the 5,10,20,40,80mmol/L digested calcium solution,respectively.Compared with other concentrations of calcium solution,bile acid contents in the supernatant and the sediment of the 5 and 10mmol/L digested calcium solution were different statist ically(P<0.05).The bile acid recoveries of dig ested solution from different calcium concetration were 95.98%~112.82%.The bile acid recovery of 40mmol/L calcium solution was lower than that of 5,10,20mmol/L calcium solution statistically(P<0.05).Conclusion Calcium with phosphorus forms sediment can combine with bile acid at the pH and the temperature similar to that of in human small intestine,and the combining capacity is the highest at calcium concentration of 20mmol/L.