Copolymer of polycaprolactone (PCL) and polylactic acid (PLA) was synthesized and catalyzed using Y (CF3COO)3/AL (I-Bu)3. The biocompatibility was evaluated by means of biochemistry, immunocytochemistry, and by cytotoxity test. This novel orthopedic biodegradable polymer can serve as an ideal orthopedic biodegradable implants, and adjustment of molecular weight and ratio of polymers can control its degradation period.