Abstract:TDE-85 was used to modify cyanate resin without affecting curing temperature. The modification was investigated by the test of viscosity-temperature characteristics, differential scanning calorimetry, fourier transform infrared spectroscopy, mechanical test, water absorption, and thermal gravimetric analysis.The results show that the viscosity of epoxy and catalyst mixture at 40℃ is less than 1Pa·s, and the sustaining time is longer than 214min that is suitable for the wet winding molding. When the epoxy content is less than 10%, the initial curing temperature does not exceed 77℃, and the gel time at 80℃ is about 30minutes that meet the requirements for low-temperature rapid curing. The modified cyanate ester resin castings with 10% of TDE-85 epoxy resin has the best overall performance and the tensile strength, flexible strength and impact strength are 46.2 MPa, 83.4 MPa and 10.8 kJ/ m 2 , respectively. However, the addition of epoxy has a negative effect on the moisture resistance and heat resistance of cyanate esters