In this work, the biocompatibility of a biomimetic, fully biodegradable ionomer phosphorylcholine (PC)-functionalized poly(butylene succinate) (PBS-PC) was investigated by means of hemolysis, platelet adhesion, protein adsorption and cytotox- icity experiments. The reference materials were poly(butylene succinate) (PBS) and chloroethylphosphoryl functionalized poly(butylene succinate) (PBS-Cl). The hemolysis rates (HR) of the leaching solutions of PBS, PBS-Cl and PBS-PC were all lower than the safe value, and the rate of PBS-PC was reduced to 1.07%. Scanning electron microscopy (SEM) measurements showed that platelet adhesion and aggregation were significant on both PBS and PBS-Cl surface. In contrast, very few platelets were observed on PBS-PC surface. Bicinchoninic acid (BCA) measurements revealed that the adsorption amounts of bovine serum albumin (BSA) and bovine plasma fibrinogen (BPF) on PBS-PC surface were 52% and 72% reduction respectively compared with those on PBS surface. Moreover, non-cytotoxicity of both PBS-PC particles and its leaching solution was sug- gested by MTT assay using mouse L929 fibroblast cells. All the results demonstrated that the biocompatibility of PBS could be greatly improved by PC end-capping strategy. This PC functionalized polyester may have potential applications in biological environments as a novel carrier for controlled drug release and scaffold for tissue engineering. In this work, the biocompatibility of a biomimetic, fully biodegradable ionomer phosphorylcholine (PC) -functionalized poly (butylene succinate) (PBS-PC) was investigated by means of hemolysis, platelet adhesion, protein adsorption and cytotox- ic experiments. The reference materials (hemolysis rates (HR) of the leaching solutions of PBS, PBS-Cl and PBS-PC were all lower than the safe value , and the rate of PBS-PC was reduced to 1.07%. Scanning electron microscopy (SEM) measurements showed that platelet adhesion and aggregation were significant on both PBS and PBS-Cl surface. In contrast, very few platelets were observed on PBS-PC Bicinchoninic acid (BCA) measurements revealed that the adsorption amounts of bovine serum albumin (BSA) and bovine plasma fibrinogen (BPF) on PBS-PC surface were 52% and 72% reduction respectively compared to those on PBS surface. Mo reover, non-cytotoxicity of both PBS-PC particles and its leaching solution was sug- gested by MTT assay using mouse L929 fibroblast cells. All the results characterized that the biocompatibility of PBS could be greatly improved by PC end-capping strategy. This PC functionalized polyester may have potential applications in biological environments as a novel carrier for controlled drug release and scaffold for tissue engineering.