Abstract: Provided are a power distribution unit and a rack system. The power distribution unit includes: a terminal block (1) having an input terminal (11) for power supply and a lead-out terminal (12) for power supply; at least one wiring pad (2) respectively electrically connected to the lead-out terminal (12); a plurality of power output terminal groups (3), each power output terminal group (3) being composed of at least one power output terminal (31), and each power output terminal (31) being electrically connected to a respective wiring pad (2); and a plurality of switch mechanisms (4) provided in such a way that a switch mechanism (4) is correspondingly provided for a power output terminal group (3), where the switch mechanism (4) causes the corresponding power output terminal group (3) to be electrically connected to or electrically disconnected from the corresponding wiring pad (2).