Background Bio-based thermoplastic composites with high-performance and low cost have attracted much interest due to their sustainability and their potential applications. The reinforcement of poly(butylene succinate) (PBS) with recycled carbon fiber (RCF) not only gives this biodegradable material excellent physical properties to compete with conventional composites, but also provides a new route to the use of RCF with well controlled cost. Results Bio-based PBS/RCF composites were prepared by simple melt extrusion through a twin-screw extruder. The evaluation of mechanical properties confirms a significant enhancement effect of RCF on PBS as a result of surface treatment of RCF with silane coupling agent. Morphological study indicates a homogeneous dispersion of RCF in the matrix due to the good interfacial interaction between fibers and PBS. The investigation of crystallinity verifies that RCF plays the role of nucleation agent in the crystallization process of PBS matrix and remarkably accelerates its crystallization rate. Conclusion The incorporation of RCF is advantageous for the enhancement of mechanical properties, heat resistance, and processability of PBS-based materials. PBS/RCF composites can be used to many fields as a low-cost biodegradable material having high performance. (c) 2012 Society of Chemical Industry.