Molecular dynamics simulation was carried out to study the behavior of liquid 1,2 dichloroethane molecules under external electric fields including direct current field, alternating current field and positive half period cosin field. The maximum applied field strength was 10 8 V/m , the maximum frequency of the alternating current field and that of the positive half period cosine field was 10 12 Hz .The simulation revealed that the field type and field strength act on the population of the molecular configuration. In the strong direct current field, all trans forms converted completely into gauche forms. Order parameter and the correlation of the system torsion angle were also investigated. The results suggested that these two dynamical parameters depended also on the field type and the field strength. The maximum of order parameter was found to be at 0.6 in the strong direct current field. Molecular dynamics simulation was carried out to study the behavior of liquid 1,2 dichloroethane molecules under external electric fields including direct current field, alternating current field and positive half period cosin field. Maximum applied field strength was 10 8 V / m, the maximum frequency of the alternating current field and that of the positive half period cosine field was 10 12 Hz. The simulation revealed that the field type and field strength act on the population of the molecular configuration. In the strong direct current field, all transforms converted completely into gauche forms. Order parameter and the correlation of the system torsion angle were also investigated. The results suggested that these two dynamical parameters depended also on the field type and the field strength. The maximum of order parameter was found to be at 0.6 in the strong direct current field.