Abstract: Cardanol novolac epoxy resin I (Epoxy-I) and cardanol novolac epoxy resin II (Epoxy-II) with higher epoxy value were synthesized from cardanol novolac resin synthesized from cardanol reacted with formaldehyde. The effects of various reaction factors on these reactions were investigated. The results showed that the optimal reaction conditions for the synthesis of cardanol novolac resin were as follows: 3% weight ratio of cardanol used as the amount of zinc acetate, the reaction temperature 90 ℃ and the reaction time 3 h. The optimal reaction conditions for the synthesis of Epoxy-I were that the amount of quaternary BTEAC was 2 % weight ratio of cardanol novolac resin, the reaction temperature was 90 ℃ and the reaction time was 4 h. And the epoxy value of Epoxy-II reaches to the highest when the amount of epoxidizing agent is 80% the weight ratio of Epoxy-I, the reaction temperature is 70 ℃ and the reaction time is 6 h. The chemical structure of both novolac epoxy resin were characterized by FT-IR and NMR spectra.