In order to meet the test efficiency and safe and reliable operation requirements of a transonic wind tunnel, the operation monitoring and fault diagnosis technology of the wind tunnel was studied. The system hardware adopts hierarchical structure to collect operation state parameters, uses software system analysis to collect data, realizes online monitoring, alarm and early warning, fault diagnosis functions, and analyses the key technology of alarm and early warning strategy setting and fault diagnosis. The practical application results show that the system can operate for a long time reliably and effectively, and has certain practical reference value.