Abstract: In view of the faults caused by aging, moisture or short circuit of zinc oxide arrester during long-term operation, a typical electrothermal coupling model is established based on the parameters of 110～500 kV arrester. The multi-physical field simulation modeling method of lightning arrester is introduced, and the calculation method of convective heat transfer coefficient on the outer wall of zinc oxide lightning arrester based on the outflow field is proposed. The change rule and function of convective heat transfer coefficient of porcelain and composite jacket zinc oxide lightning arrester are obtained. The validity of the calculation results of convective heat transfer coefficient is verified by comparing the electro-thermal coupling calculation with the three-dimensional fluid-thermal coupling temperature field calculation. It can provide numerical reference for multi-physical field simulation of arrester.