Using LabVIEW software and acquisition equipment, the position transducer (LVDT) measuring system on large telescope based on virtual instrument technique was developed. The position transducer on the large telescope was measured, the sensitivity, fundamental error, linearity, repeatability, reverse running error was obtained, in order to provide foundation for primary mirror position resolving of large telescope next. The result of test indicated that the measurement system satisfied the requirement of position transducer measurement, the interface is friendly, the accuracy of position transducer reached the requirement of position resolving, this measurement system had certain common ability, this system can be used in other position transducer.