Polylactide (PLA) fibre reinforced poly(trimethylene carbonate) (PTMC) composites were prepared by incorporating electrospun fibres in tri-functional methacrylate-terminated PTMC macromer solutions and cured by UV irradiation. Short electrospun fibres with average length of 50–700 μm were prepared by solvent assisted mechanical stirring and different amounts of short fibres were loaded into PTMC composites. The reinforcement effect of short PLA fibres at different concentrations and continuous fibre were assessed by tensile tests and micromechanical models. With the incorporation of continuous electrospun PLA fibres, the Young’s modulus of PTMC was increased from 2.7 to 310 MPa; while tensile strength and toughness were also improved significantly. The addition of small amounts (5 wt%) of short PLA fibres increased the Young’s modulus and tensile strength three-fold without compromising the ductility of PTMC. The potential to tailor the mechanical performance and dimensional stability of these nontoxic and degradable PTMC/fibre composites makes them interesting candidates for tissue engineering applications.