A computer stick docking system and a power management method thereof are provided. The computer stick docking system includes a docking station and a computer stick device. The docking station is configured to receive a display device and a computer stick device, including a docking battery and a docking HDMI interface circuit. The computer stick device includes a computer-stick controller and a computer-stick HDMI interface circuit. The computer-stick controller is configured to load an operating system. The computer-stick HDMI interface circuit, coupled to the computer-stick controller, is configured to request battery power information of the docking battery from the docking station after it is powered on and the computer-stick HDMI interface circuit is connected to the docking station.