Abstract: Poly(3,4-dihydroxycinnamic acid)-b-poly(ethylene glycol) (PDHCA-b-PEG) copolymers were synthesized by thermal polycondensation of 3,4-dihydroxycinnamic acid (DHCA) and poly(ethylene glycol) (PEG). The structures and molecular weight of PDHCA-b-PEG copolymers were characterized by nuclear magnetic resonance (1H-NMR), Fourier transform infrared (FT-IR) and gel permeation chromatography (GPC). Properties of the polyester were investigated by differential scanning calorimeter (DSC), fluorescence spectroscopy and X-ray diffraction (XRD). It is proved that PDHCA-b-PEG copolymers have evident glass transition temperature (Tg). The polyester has the lowest Tg of 73 ℃ when the mass ratio of PEG to DHCA was 15%. The fluorescence spectroscopy shows the PDHCA-b-PEG copolymer solution has the strongest fluorescence emission when the mass ratio of PEG to DHCA was 5%. The X-ray diffraction (XRD) results indicate that PDHCA and PDHCA-b-PEG are amorphous and these copolymers have good biodegradation performance. Bacterial culture in vitro shows the PDHCA-b-PEG copolymer solutions have inhibition against staphylococcus albus bacteria.