Poly(butylene fumarate) (PBF) bearing reactive double bonds on the polymer main chains has been designed and synthesized by coupling with hexamethylene diisocyanate (HDI) under very mild condition. The chemical structure, conformational structure, crystal structure and molecular weight of PBF were systematically characterized by ATR-FTIR, H-1 NMR, C-13 NMR, GPC and WARD. The thermal properties, mechanical properties and biodegradability of PBF were carefully studied by DSC, mechanical testing and enzymatic degradation. The results of H-1 NMR and C-13 NMR spectra indicate that no isomerization or Ordelt saturation reaction of trans C=C took place during the bulk polymerization and the reaction just proceeded in the way we designed. Linear PBF with high-molecular-weight has been successfully synthesized. This new type of uncrosslinked polyester is shown to have many merits such as relatively high melting point (T-m), satisfactory processability and good mechanical properties. The impact strength of PBF is higher than 200 J/m; tensile and flexural strength can reach to 41.0 and 26.7 MPa, respectively. (C) 2012 Elsevier Ltd. All rights reserved.