A method tests hard disk ports located on a motherboard of a computing device. Each of the hard disk ports connects to a respective serial port of a test fixture. The test fixture includes a group of serial ports, a multiplexer and a storage device. Each of the hard disk ports is selected to be tested during the process of hard disk ports test. A data transmission path is formed by building a connection between the storage device and a channel of the multiplexer corresponding to the hard disk port. Data are written to the storage device and read from the storage device through the data transmission path. The hard disk port is working normal if the written data are identical to the read data. The hard disk port is not working normally if the written data are not identical to the read data.