A series of novel rosin-based siloxane epoxy resins (AESE copolymers) were prepared by the reaction of ethylene glycol diglycidyl ether modified acrylpimaric acid (AP-EGDE) with poly(methylphenylsiloxane). The chemical structures of the produced epoxy resins were determined by FTIR, H-1-NMR, C-13-NMR, and epoxy equivalent weight (EEW) test. After modification, the tensile strengths of AESE (20-40) are slightly lower than that of AP-EGDE; however their breaking elongations are higher than that of AP-EGDE remarkably. TGA results reveal that the thermal stability of AESE serial:: is better than that of AP-EGDE due to the formation of a protective residue. The char residue of AESE increases at 700 degrees C with its silicon content increases. Nevertheless, there is a peak LOI value for AESE when its silicon content is 30%. Moreover, the chemical structures of char at the end of the LOI test were analyzed by FTIR The results confirmed the formation of the protective residue.