The present disclosure provides a power distribution apparatus, a battery pack, and a vehicle. The power distribution apparatus includes: a base, the base being configured with an interface area, a high-voltage connection part and a low-voltage connection part being fixed in the interface area; a high-voltage loop, at least a portion of the high-voltage loop being arranged on the base, the high-voltage loop overlapping with the high-voltage connection part for electrical connection, the high-voltage loop having a battery positive-electrode connection end and a battery negative-electrode connection end, components connected in the high-voltage loop being electrically connected through overlapping, the high-voltage loop including a main disconnecting switch core, and the main disconnecting switch core being fixed on the base and the main disconnecting switch core and the base jointly forming a first module; a circuit board, the circuit board being arranged on the base; and a low-voltage loop, the low-voltage loop being integrated into the circuit board and the low-voltage loop and the circuit board jointly forming a second module, and the high-voltage loop and the low-voltage connection part being respectively plugged into the circuit board and electrically connected to the low-voltage loop. The power distribution apparatus in the embodiments of the present disclosure has advantages such as a simple and compact structure space utilization, a small volume, a light weight, low costs, versatility and high production efficiency.