The invention discloses a serial port communication based pressure testing method. The method comprises the steps that a transmitting end TX and a receiving end RX of a test-needed serial port communication link are in short circuit, and a transmitting end TX and a receiving end RX of a test tool are connected with the serial port communication link; data parameters of the test tool are configured, and transmitting and receiving are carried out on data, and contrastive analysis is carried out to judge whether transmitting data are matched with receiving data or not; a matching result is shown, it is judged whether the testing continues to be carried out or not according to the matching result; when the testing is needed to be continued, transmitting data parameters are changed to exert pressure on the serial port communication link, and an optimal performance index of the serial port communication link is obtained. According to the serial port communication based pressure testing method, the communication is guaranteed to be stable according to various types of test mechanisms, whether the serial port communication is normal or not can be tested, the optimal performance index of the serial port communication can be tested, and therefore the stability and the reliability of the serial port communication are guaranteed.