A hub device and a power supply method thereof are provided. The hub device includes a power input port, first and second power output ports, a power management circuit and a controller. When first and second electronic devices are respectively connected to the first and second power output ports, the controller determines an input electric power from at least one default supply power of the power adapter based on first operating power information of the first electronic device and second operating power information of the second electronic device, so as to control the power adapter to provide the input electric power to the power input port. The power management circuit receives the input electric power to generate first and second operating power, so as to output the first operating power to the first power output port and output the second operating power to the second power output port.