Boiling heat transfer is one of the most efficient modes of heat transfer. The most widely used regime is perhaps the nucleate boiling. In nucleate boiling, very high wall heat fluxes can be achieved at low superheats. The heat transfer duty of heat exchangers can be improved by heat transfer enhancement techniques. In general, these techniques divided into two groups of active and passive techniques. Applying electrical field have been introduced as one of the type of active heat transfer enhancement techniques. In this study, a two-dimensional axisymmetric model on growth and departure of a single bubble have been presented. To validate the present model, the simulation results in absence of electric field, including the bubble departure diameter and departure time were compared with the experiment and numerical data. Then, the effects of electric field on bubble characteristics were studied. The phase-field method was employed to track the interface between the gas-liquid two-phases. The phase field method has been adopted to capture the vapor-liquid interface. By solving the coupling problems of fluid flow, thermal and electric filed along with the phase-field equation, the effect of an applied electric field on heat transfer and flows of a vapor bubble surrounded by saturated water were studied and simulated numerically. A vapor bubble nucleus initially attached to a superheated wall and grew with two different contact angle of 50° and 90° at superheats of 7, 8.5 and 10°C. The bubble growing size and bubble departure time were increased and decreased, with increasing in the wall superheat, respectively. Also, increase in contact angle has changed the velocity field and temperature field around the base of bubble and increase the departure diameter and departure time. The predicted errors in the case with contact angle 50°, compared to experimental data were 16% for departure time and 8% for departure diameter. In addition, for contact angle of 90°, results were consistent with the available numerical data in literatures with error less than 10%. Then, effect of applied electric field on bubble characteristics such as velocity field, growth time, waiting time, departure frequency and departure diameter were discussed. The bubble growth time and waiting time were decreased as the electric field strength increase. Consequently, the bubble departure frequency was increased by increasing the applied voltage. In contact angle of 50° and wall superheat of 7°C, bubble was detached from heated wall after 50.4ms with diameter of 2.91mm. But, upon applying the 4000V voltage, departure time and departure diameter were decreased to 23.2ms and 1mm, respectively. Application of electric field resulted in raising the number of detached bubbles from the superheated wall in a certain time interval, and decreasing of the bubbles departure size and elongates bubbles, were resulted in a change in the temperature field over the domain, and enhancing the rate of heat flux. A non-linear relation was existed between the applied voltage and the heat flux. For example, application of imposed electrical voltage of 4kV, resulted in decreasing of the thickness of thermal boundary layer at the right end of computational domain in presence of 60%, and increasing of the heat flux up to 85%. Keywords: Nucleate boiling, enhanced heat transfer, phase field method, electrohydrodynamic.