β-tricalcium phosphate(β-TCP) was modified by using stearic acid,and the mechanism of interfacial interactions between β-TCP particles and stearic acid was studied by transmission electron microscopy(TEM),thermal gravimetric analyzer(TGA) and X-ray photoelectron spectroscopy(XPS).The β-TCP/PLLA and modified β-TCP/PLLA composite nanofiber membranes of different quality ratios were prepared by electrospinning.Their morphologies were observed by using scanning electron microscope(SEM) and their mechanical properties were also studied.The results indicated that the stearic acid was coated on the surface of β-TCP particles,and modified β-TCP was hydrophobic.H+ of stearic acid could produce protonation reaction with O of PO3-4 from β-TCP and then generate —OH.The modification of β-TCP particles by stearic acid could reduce their agglomeration and obtain the continuous and uniform nanofibers.The mechanical properties of the modified β-TCP/PLLA composite nanofiber membranes were improved more significantly than that of β-TCP/PLLA.