The invention discloses a portable load transfer power box for DC cabinet replacement, comprising a rectifying device, a battery pack, a feeder switch, a control device, a first output end, a second output end and a third output end, wherein the input end of the rectifying device is connected to a mains interface; the mains interface is also connected to the control device; the control device is also connected to the feeder switch; the output end of the rectifying device is connected to the battery pack; the battery pack is also connected to the feeder switch; and the feeder switch is also connected to the first output end, the second output end, and the third output end. The various parts of a standby power supply of the DC cabinet of a substation are integrated into one system and only afew module circuits are used, thereby reducing volume and weight and improving the portability. In addition, the built-in control device can accurately set an output voltage, ensures power quality, and improves the operational stability of a secondary power load.