Cyanate ester (CE) was employed to modify epoxy resin (EP) by chemical reaction, and the thermal, mechanical, and corrosion properties were systematically studied. Differential scanning calorimetry and Fourier transform infrared spectra were carried out to determine the curing kinetic parameters, suitable curing procedure, and reaction mechanism. The glass transition temperature and thermal stability were investigated employing dynamic mechanical thermal analysis and thermogravimetry measurement. Furthermore, the mechanical and corrosive properties were evaluated, using test techniques such as mechanical testing machine, abrasion tester, axle rod flexibility tester, scanning electron microscope, and electrochemical impedance spectroscopy. Results verified that an appropriate amount of CE could significantly improve the comprehensive performance of EP. However, a satisfactory effect would not be achieved when the modifier is inadequate or excessive.