Biodegradable block tercopolymers were synthesized by bulk ring-opening copolymerization of trimethylene carbonate (TMC), L-lactide (LLA) and e-caprolactone (epsilon-CL) at different feed molar ratios. The molecular structure of the tri-block copolymer was confirmed by H-1 NMR, C-13 NMR and FT-IR analysis. Nano-structured fibers of the obtained tri-block tercopolymers were prepared by electrospinning technique. XRD spectra of the nanofibers showed that the polymer chain orientation enhanced and the crystallinity increased during the electrospinning process. The mechanical properties of the nanostructured fibers can be adjusted by changing the compositions of the copolymers. The biodegradability of the nanofibers was investigated by intrinsic viscosity change and SEM photos. The viscosity of the nanofibers, which derived from the tri-block copolymers, decreased gradually with degradation time. The SEM photos showed that the morphology change of the tri-block copolymers was related to the composition of the copolymer after the degradation time of 225 days. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.