Continuous pump and transmission of charges such as calcium, potassium, sodium in the cell can induce time-varying electromagnetic field, and the induced electric field can further modulate the propagation of ions in the cell. Based on the physical laws of static electric field, the effect of electric field in isolate neuron is investigated by introducing additive variable E on the model. Each neuron is considered as a charged body with complex distribution of charges, and electric field is triggered to receive and give response to external electric field and electric stimulus. That is, the electric field is considered as a new variable to describe the polarization modulation of media resulting from external electric field and intrinsic change of density distribution in charges or ions. The dynamical behaviors in electrical activities are analyzed and discussed in the new neuron model, and it confirms that electric field can cause distinct mode transition in electrical activities of neuron exposed to different kinds of electric field. It could provide new insights to understand signal encoding and propagation in nervous system. Finally, it also suggests that new model can be used for signal propagation between neurons when synapse coupling is suppressed.