In an effort to decrease the aggregation of tetracalcium phosphate (TTCP, Ca 4 (PO 4 ) 2 O) in composites and develop better bone substitute materials, a series of poly(l-lactic acid) (PLLA)-grafted TTCP (g-TTCP) particles were prepared by a ring-opening polymerization with l-lactide (the monomer for synthesizing PLLA) in the presence of catalyst stannous octoate [Sn(Oct) 2 ]. The g-TTCP/poly(1,4-butylene succinate) (PBS) composites with the different g-TTCP contents were prepared via melting processing. The bonding between the PLLA and the TTCP particles was analyzed by FTIR, TG, 1 H NMR and XPS. The results confirmed that the PLLA was grafted on the surface of the TTCP particles. Time-dependent phase monitoring indicated that the g-TTCP had enhanced dispersion in the PBS solution. Water contact angle measurement and cell culture were also used to investigate the properties of the g-TTCP/PBS composites. The g-TTCP in composites provided more favorable environments for rat osteoblast to attach and grow on the surface of the g-TTCP/PBS composites. Cell proliferated well in the extracted solution of the g-TTCP/PBS composites with different g-TTCP content, and there was no necrotic or suspended cells appeared.