Aiming to develop a biomaterial with excellent biocompability, a novel β-cyclodextrin modified polylactic acid (PLA-β-CD) was synthesized by N-acylation reaction of MPLA (maleic anhydride modified poly(d,l-lactic acid)) using hydrophilic mono(6-(2-aminoethyl)-amino-6-deoxy)- β-cyclodextrin(β-CD-6-E) as acylating agent. Surface wettability and blood biocompatibility of PLA-β-CD were investigated. The tests indicated that the static water contact angle of PLA-β-CD was decreased from 76.7º to 72.1º comparing with PLA. The morphology of blood platelets adhered on the surface of PLA-β-CD was observed by scanning, and only a few platelets, round and not aggregated. The results revealed that the blood compatibility of PLA-β-CD was better than PLA.