Bridge SAS signal channel testing system and testing method thereof

The invention discloses a bridge SAS signal channel testing system and a testing method thereof, which are used for testing whether testing signals stored in a terminal device are correct or not. The testing system comprises a control end, a hot plug bridge interface, a back plate, an adaptor plate and a terminal device. The control end is used for sending a testing signal, and detecting a signal which is to be detected and is transmitted by the terminal device, and selecting an SAS interface as a transmitting path for sending the testing signal. The hot plug bridge interface is electrically connected with the control end, and the hot plug bridge interface is used for receiving and converting the testing signals sent by the control end. The adaptor plate is electrically connected between the hot plug bridge interface and the terminal device, and is used for converting the low-voltage differential signals of the hot plug bridge interface to the SAS signal channels, and transmitting the low-voltage differential signals to the terminal device. The control end judges whether the terminal device normally works or not according to the received response signals.