A power supply device for supplying power to a server and a power supply management system are provided. The device includes: a power supply control chip, a first connector, a voltage comparator, a counter and a resistance regulation circuit. The resistance regulation circuit includes a pull-up resistance circuit and a pull-down resistance circuit including multiple resistor branches and switches. An input terminal of the voltage comparator is connected to an address input terminal, the other input terminal of the voltage comparator is connected to a connection point of the resistance regulation circuit. An input terminal of the counter is connected to an output terminal of the voltage comparator, each output terminal of the counter is connected to one switch and controls a state of the switch. Each output terminal of the counter is connected to one address pin of the power supply control chip.