Biphasic calcium phosphate (BCP)/poly L-lactide (PLLA) biocomposite is proven to be a promising bone graft material or scaffold for bone tissue engineering. To improve the interfacial compatibility of BCP bioceramic with biopolymer-PLLA, BCP powders were surface-modified in different condition to graft polymer groups onto the surface of the BCP powders. L-lactide and L-lactic acid (LA) oligomer were used to modify the BCP surface with stannous octanoate (Sn(Oct)(2)) and stannous chloride (SnCl2) as catalyst, respectively. Results show that the surface modification effect is obvious and the amount of grafted organic group is above 6.5 wt.%. Sn(Oct)(2) and SnCl2 are the optimal catalysts for the surface grafting reaction of L-lactide and L-LA oligomer, respectively. The surface grafting slightly increase the particle size of BCP powders and reduce the tendency for their agglomeration. (C) 2008 Published by Elsevier B.V.