A hot plugging module power supply device, method and system are provided. When a hot plugging module is connected to a system in a hot plugging manner, a control unit transmits a first control signal to a signal processing unit. The signal processing unit forms a switch-on signal and transmits the switch-on signal to a switch unit, to gradually switch on the switch unit, to provide power to the hot plugging module. During the hot plugging module is supplied with power, when an overcurrent fault occurs in the hot plugging module, the control unit transmits a second control signal to the signal processing unit, and the signal processing unit forms a switch-off signal and transmits the switch-off signal to the switch unit, to immediately switch off the switch unit, to stop supplying power to the hot plugging module.