A power conversion apparatus is provided. The power conversion apparatus receives an AC input power by an input side and includes a capacitor, an AC-to-DC conversion unit and a discharge unit. The capacitor is connected with the input side. The AC-to-DC conversion unit is coupled to the input side, and configured to convert the AC input power after receiving the AC input power to generate a DC output power. The discharge unit is coupled to the capacitor and has at least two switch elements. The discharge unit enables the at least two switch elements when supply of the AC input power is interrupted, such that one of a first discharge path and a second discharge path formed by the at least two switch elements is taken to discharge or drain the energy stored in the capacitor.