A power conversion apparatus and control method thereof are provided. The power conversion apparatus includes an output capacitor, an AC-to-DC conversion circuit, a transformer-based auxiliary circuit, an inrush suppression component and a switching circuit. The AC-to-DC conversion circuit is configured to convert an AC power into a DC power. The auxiliary circuit provides a leakage inductance energy. The inrush suppression component provides a first conduction path, and the switching circuit provides a second conduction path. When the switching circuit cuts off the second conduction path in response to the leakage inductance energy, the AC-to-DC conversion circuit conducts the DC power to the output capacitor via the first conduction path. When the switching circuit turns on the second conduction path in response to the leakage inductance energy, the AC-to-DC conversion circuit conducts the DC power to the output capacitor via the second conduction path.