The arc temperature field, electric field and size of conducting zone of gliding arc plasma are important parameters to determine the temperature and density of the electrons, the chemical reaction rates and energy efficiency. Electrical parameters of a 50 Hz ac gliding arc discharge were measured under conditions of two gas flow rates, 1.43 L/min and 6.42 L/min. An instantaneous model which was used to describe the energy transfer of gliding arc discharge was simplified by using an approximate expression for the electrical conductivity and diffusivity of plasma, which ravelled out the moving boundary in the gliding arc simulation resulting from variation of arc structure. The current density, electric field, dynamic temperature field and the structure of ac gliding arc was calculated. The electric field strength from the simulation result of the model was in agreement with the experimental data. According to the calculational result, the temperature on the axis of arc reached as high as 5700—6700 K. It showed the gas flow directly affected the arc structure and current density, thus further affected the electric field strength and temperature distribution. The electric field strength increased firstly and then decreased during a discharge period.