This paper is to demonstrate that the presence of an electric field can be used to control materials microstructure formation. Special efforts have been made to identify the foremost process control parameters that affect the interface dynamics, and thermoelectric effects on materials microstructure formation during directional solidification. A computational model that integrates microscopic analysis to macroscopic model has been developed and applied to directional solidification of BiMn/Bi eutectic in the presence of electric fields. Numerical results demonstrated that in addition to process parameters, microstructure formation strongly depends on intensity, polarity and duration of applied current, and it changes spontaneously as an electric field is applied. Predicted patterns of microstructures have qualitatively agreed with the experiments. The results indicate the feasibility of utilizing electric fields to control microstructure formation during eutectic growth.