This study presents a closed-loop recycling process for carbon fibers using supercritical n-butanol. In the reclamation process, to achieve the highest composite recovery efficiency, the degradation of the carbon fiber-reinforced epoxy resin composites was conducted at various experimental feedstock ratios (ratio of composite waste to n-butanol), then the reclaimed carbon fiber (RCF) was characterized using various methods to develop an understanding of the changes in the properties and morphologies. In the remanufacturing process, in order to evaluate the reusability of the RCFs and the feasibility of the closed-loop recycling process for carbon fibers, the RCFs were mixed with new epoxy resin and polypropylene to remanufacture the composites, and then the mechanical properties of remanufacture composites were tested. The results show that, under an optimized process, the maximum recovery efficiency (feedstock ratio) of the composite was 0.1 g/ml. The impact of reclamation process on RCF lies in the degradation of tensile properties and the removal of sizing agent, which leads the change of the interfacial bonding strength between RCF and new resin, and eventually results in an impact on the performance of remanufacture composites. Compared with the virgin carbon fiber-reinforced composites, the improvement in the RCF-reinforced polypropylene properties and insubstantial variations in the tensile properties of the RCF validate the potential of the closed-loop recycling process for carbon fibers.