An electric separating apparatus has a separating tank and an electrical control. The separating tank has at least one first electrode panel, a second electrode panel, an upper separating region and a lower separating region. The electrode panels are vertically mounted in the separating tank to form the separating regions. The electrical control is electrically connected to the separating tank and has a transformer, a high-power resistor, a first A/C transformer, a second A/C transformer and a control unit. The transformer is electrically connected to an A/C source and the electrode panels. The high-power resistor is electrically connected to the transformer and the at least one first electrode panel in series. The A/C transformers are respectively connected to the high-power resistor and the electrode panels. The control unit is electrically connected to the A/C transformers to determine an electrical impedance of a liquid mixture in the tank.