To predict the charged species distributions in the ethanol-air flame, an improved reaction mechanism is proposed. The detailed reaction mechanism involving neutral species for the combustion of ethanol is combined with a set of ionic reactions to account for the charged species chemistry. The new chemical-kinetic mechanism consists of 64 species and 423 reactions. Simulation of ethanol-air flame involving charged species is conducted by using the model based on the proposed mechanism. The present model is validated by the experimental results. The ethanol-air flame temperature, neutral and charged species distributions are reasonably predicted by the present model. Although the concentrations of charged species are much lower than that of neutral species, the charged species have an important effect on the flame characteristics, especially under the electric field. Electrons are the main negative charged species and H3O+ is the main positive charged species in the ethanol-air flame. The results of pathway analysis and sensitivity analysis show the crucial roles of H3O+ and the reactions involving it for the charged species chemistry. When the electric field is applied, the present model has a better performance in predicting the diffusion ethanol-air flame compared with the model without charged species.