•Recovery ratios of carbon fiber are both more than 90.00% by two-step microwave and traditional thermolysis methods.•The epoxy resin of carbon fiber surface is decomposed at the first step, and then the char is oxidized at the second step.•The microwave method is faster, obtains higher recovery ratio and requires less energy than that of traditional method.•This study provides a new and effective way to recycle carbon fiber reinforced resin matrix composites, and shows great application potentials. In this study, a novel two-step thermolysis method was proposed to recycle the carbon fibers with excellent properties from the wastes of carbon fiber-reinforced polymer composites (CFRP). The epoxy resins on carbon fiber surface were decomposed at the first step, followed by the oxidation of the char at the second step. The carbon fibers were successfully recovered by microwave and traditional two-step thermolysis with the recovery ratio of 94.49% and 93.47%, respectively. The recovered carbon fibers (RCF) were characterised using thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Compared with the traditional heating method, the microwave heating method demonstrated the merits of faster operation, higher recovery ratio and less energy consumption.