A system for testing sleep and wake functions of a computer includes a test device and a test software installed on a motherboard of the computer. The test device includes a timing module, a counting module, and a switch module. The test software includes an initialization unit, a signal transmission unit, and a comparison unit. The test device communicates with the motherboard, and an operation system of the computer sets that receiving a control signal means executing an operation of putting the computer to sleep or waking the computer up. The system employs the test software cooperating with the test device to test sleep and wake functions of the computer automatically.