A test board is provided. The test board includes a power connecting interface, diode modules, a power module a detecting module, and a processor. The power connecting interface includes power pins, wherein each of the power pins is electrically connected to a motherboard power socket to receive a power signal. Each of the diode modules is electrically connected to one of the power pins and includes at least one diode. The power module is electrically connected to the diode modules to receive the power signal through each of the diode modules. The detection module is electrically connected to points between the diode modules and the power connecting interface to generate a detection result according to the voltage between each diode module and the power connecting interface. The processor is used to determine the connecting state between the power pin and the corresponding motherboard power socket according to the detection result.