Poly(L-lactide-co-trimethylene carbonate) (PLT) copolymers were synthesized by ring opening polymerization of L-lactide (LLA) and trimethylene carbonate (TMC). The resulting copolymers were characterized by using 1H NMR, GPC, DSC and tensile tests. The copolymer properties are dependent on the TMC content. In vitro degradation of copolymers was carried out in pH 7.4 phosphate buffered saline at 37 °C. The results show that copolymers with higher TMC content are more resistant to degradation. The cytotoxicity and hemocompatibility of copolymers were evaluated from MTT assay, hemolysis test, dynamic clotting time and plasma recalcification time. Results indicate that the copolymers present very low cytotoxicity and good hemocompatibility.Cardiac occluders were designed and fabricated using 3D printing. In vivo degradation of occluders was realized by intramuscular implantation in the back of rabbits. The occluders were almost totally degraded in 120 days. Visual observation and H&E staining analysis confirmed the good tissue compatibility of occluders. All these findings suggest that PLLA-TMC copolymers could be promising for potential applications as degradable occluder material.