Abstract: The anacardic acid based epoxy resin type-Ⅰ(EACA-Ⅰ) was synthesized by the reaction of anacardic acid(ACA) obtained from cashew nut shell liquid(CNSL) and epichlorohydrin. Then, the side chain oxidation of EACA-Ⅰ was carried out to form the anacardic acid based epoxy resin type-Ⅱ(EACA-Ⅱ). The chemical structure of the epoxy resins was characterized by HPLC, FT-IR and NMR. The epoxy values of EACA-Ⅰ and EACA-Ⅱ were 3.7 mmol/g and 6.0 mmol/g, and the viscosities at 25 ℃ were 80 and 300 mPa·s, respectively. The characterization of curing reaction and heat resistance of the cured products obtained from the reaction of epoxy resins with tetrahydromethyl-1, 3-isobenzofurandione(MeHHPA) and isophorondiamine(IPDA) were investigated by DSC and TGA, respectively. The results showed that the heat release of the curing process of the anacardic acid based epoxy resins with MeHHPA was moderate. However, the heat release of the curing process of anacardic acid based epoxy resin with IPDA was intense; the cured products obtained from the reaction of the anacardic acid based epoxy resins with MeHHPA showed good thermal stability with the initial temperature of degradation more than 371.6 ℃ and the peak temperature of weight loss at 417.5 ℃.