In a method for testing serial attached SCSI (SAS) ports of a server using a computing device, the computing device connects to an oscilloscope and a mechanical arm that is equipped with a test fixture having a probe. The mechanical arm controls the probe to be plugged into one of the SAS ports. The method adjusts an intensity grade of the SAS signals through the SAS port, and controls the SAS port to generate a SAS signal corresponding to the intensity grade. The test fixture obtains the SAS signal from the SAS port, and the oscilloscope measures test parameters of the SAS signal. The method analyzes values of the test parameters to find an optimal SAS signal, determines an intensity grade of the optimal SAS signal as a driving parameter of the SAS port, and accordingly generates a test report of the SAS ports.