Boron nitride nanosheets (BNNSs) were synthe-sized by the classical chemical vapor deposition (CVD) method and modified by tannic acid (TA) (named as M-BNNSs). M-BNNSs have greatly improved the thermal conductivity (0.45 W/(m.K)) and mechanical tensile strength (15.10 MPa) of epoxy resin (EP). More importantly, the EP composite coating with an appropriate amount of M-BNNS not only has an excellent anticorrosion effect (the I-corr of 10%M-BNNS@EP is 8.053 X 10(-7) A/cm(2 )after immersed in 3.5 wt % NaCl solution for 30 min) on the metal substrates but also has a good anticorrosion stability. The impedance modulus (vertical bar Z vertical bar(0.01)) of the 10%M-BNNS@EP coating is higher than that of the neat EP coating and other composite coating systems during 120 h of immersion. Polarization curve (Tafel) and electrochemical impedance spectroscopy (EIS) tests reveal that the 10%M-BNNS@EP coating not only has an excellent anticorrosion effect on the metal substrates but also has a good anticorrosion stability after being immersed in 3.5 wt % NaCl aqueous solution for 120 h.