Testing device for SAS (Serial Attached SCSI) back plate

The invention discloses a testing device for an SAS (Serial Attached SCSI) back plate, which is suitable for testing one SAS back plate. The SAS back plate is provided with a plurality of SAS connecting ports. The testing device for an SAS back plate comprises a control module, a terminal module and a signal returning module, wherein the control module is used for sending a control command; and the terminal module comprises a physical layer integrated circuit and a control element. The control element receives the control command and commands the physical layer integrated circuit to send a testing signal to the SAS back plate. The signal returning module is electrically connected to the SAS back plate and returns the testing signal coming from the SAS back plate to the SAS back plate. The SAS back plate receives the returned testing signal and then sends the returned testing signal to the physical layer integrated circuit. The physical layer integrated circuit compares the returned testing signal with the send testing signal and then records a comparison result.