A novel benzoxazine-based phenolic resin containing furan groups and long alkyl side-chain (CFB) was synthesized using cardanol-furfural resin as phenolic raw materials. The new benzoxazine-based cardanol-furfural resin derived from renewable resources was characterized by FTIR, 1H NMR spectra and Differential scanning calorimeter (DSC) etc. The thermal ring-opening reaction of the benzoxazine ring and the polymerization of the double bond were demonstrated with FTIR measurement. The thermal behavior of the cured product was also investigated with thermogravimetric analysis. The corresponding polybenzoxazine showed Tg value higher than that of polybenzoxazine prepared from cardanol, ammonia and formaldehyde. The char yield value at 800°C of the corresponding polybenzoxazine is 46.2% in N2 atmosphere. The results showed that the polybenzoxazine cured from CFB had good heat resistance and toughness.