To realize demulsification and dewatering treatment efficiently in the process of industrial waste oil recovery, the device using high voltage electric field to enhance the separation efficiency of hydrocyclone is proposed. The distribution of the flow field inside the strengthened device affects the separation efficiency of the device directly, however, it is complicated and unclear at present. By establishing the centrifugal separation device strengthened by electric field and combining the control equations of electric field and droplet size, the internal flow fields of the device with five different strengthening voltages were numerically simulated. The numerical results show that when the strengthening voltage is 11kV, the maximum increase of the tangential velocity of the mixture inside the device is 15%, the maximum decrease of axial velocity is 20%, and the pressure gradient of the underflow pipe section increases, which improves the separation efficiency of the device effectively. The experimental results show that the numerical model of the device strengthened by electric field reveals the distribution law of complex flow field inside the centrifugal separation device strengthened by electric field.