The rheological behavior, curing reaction characteristic, heat resistance and dielectric properties of modified cyanate ester have been studied by rheometer, differential scanning calorimetry(DSC), dynamic mechanical analyzer(DMA), thermogravimetic analysis and dielectric properties testing. The results show that the viscosity of modified cyanate ester is lower than 500 mPa·s when the temperature is between 90℃ and 170℃, and the viscosity is 280 mPa·s and pot life is longer than 10 h at the temperature of 90℃. The activation energy and the reaction order of the curing reactions are 39. 5 kJ/ mol and 0. 89, respectively. The glass transition temperature and the thermal decomposition is 294℃ and 420℃. The dielectric constant is 2. 85 and loss tangent is less than 5×10-3.