Abstract: In accordance with the present status of measurement of fan performance with burdensome in labors, low in accuracy and backward in testing method, auto-testing system for fan performance based on Virtual Instruments(VI) technology was developed. The system integrated sensor technology, computer technology and measurement technology. As a result, the system can not only automatically acquire, process testing data and express the final results in suitable forms but also control and adjust different working loads. The whole system is friendly in interface, easy in operation and complete in functions. The experiment results showed that the stability of the experiment process increased, the reading error was avoided and the measurement accuracy and experiment efficiency were improved. The system has been widely applied to many fan production factories and research institutes.