Abstract: Experimental studies have been conducted to show the effect of electric field on insulator icing. However, the motion process of droplets and its influence mechanism on the growth of ice dendrites under different types of voltages have not been understood. In the research, based on electromagnetism, hydrodynamics and field charging theory, the force characteristics and motion deviation features of the droplets under different electric fields were compared and analyzed by numerical simulations. On this basis, the impact of electric field on icing growth process was explained combined with icing tests. The results indicate that the trajectory of charged droplet presents oscillating in AC electric field, and the capture time of the droplet is 1.15 times that of DC. The normal electric field at the edge of the shed is the largest under DC, and ice branches are concentrated in this area. Since the electric force on the charged droplet has a counteracting effect in one cycle in the case of AC, the number of the droplets captured by the insulator per unit time is less than that of DC. Consequently, ice amount and length of icing insulator under DC are 13.7% and 8.75% higher than those under AC, respectively.