Chitosan-modified PLA (CMPLA) was fabricated to improve cytocompatibility of polylactide (PLA). PMAA-grafted PLA (PMAA-PLA) was obtained through alpha-methacrylic acid (MAA) grafted polymerization on PLA surface with photooxidization and UV irradiation. Steady PMAA-PLA microparticle Suspension with an average size as 172.8 +/- 3.6 nm and zeta potential as -95.0 +/- 0.6 mV was prepared through solvent volatilization. By static electricity interaction and other interactions between PMAA-PLA microsparticles and chitosan molecules, CMPLA was obtained. FTIR, XPS, SEM, and zeta potential analyses indicated that CMPLA was modified with chitosan molecules uniformly. Compared with the PLA control, CMPLA adapted to supporting the attachment and proliferation of L929 cells better. The obtained CMPLA was expected to be used as perfect biomaterial for tissue regeneration. (C) 2008 Wiley Periodicals, Inc.