The investigation on bubble behavior in electric field helps to analyze the mechanism of electric en- hancement of boiling heat transfer. Experiments were performed to investigate the bubble deformation in direct current (DC) electric field with bubbles attached to the orifice. The air bubbles were slowly generated in the trans- former oil pool at different orifices, so that the effect of flow on bubble shape was eliminated. The results showed that the bubbles were elongated and the departure volume decreased when the electric field was intensified. The major and minor axes, aspect ratio and departure volume increased with increasing the orifice diameter. Both the electric field and orifice size have great influence on bubble behavior. The bubble deformation was also simulated to compare with the experimental results. The numerical and experimental data qualitatively agree with each other. The investigation on bubble behavior in electric field helps to analyze the mechanism of electric en- hancement of boiling heat transfer. Experiments were performed to investigate the bubble deformation in direct current (DC) electric field with bubbles attached to the orifice. slowly generated in the trans- former oil pool at different orifices, so that the effect of flow on bubble shape was eliminated. The results of that bubbles were bubble shaped was and the departure volume decreased when the electric field was intensified. The major and minor axes Both the electric field and orifice size have great influence on bubble diameter. Both numerical simulation and compare with the experimental results. The numerical and experimental data qualitatively agree with each other .