Abstract: Directing against the disadvantage of the complicated hardware and high cost of traditional eddy current testing instrument, a LabVIEW based eddy current testing system was developed. The system was composed of hardware circuit, computer, data acquisition card and relative software. The design of the carrier frequency generator, auto-balance circuit and the phase-sensitive detector was introduced in detail. Testing experiments were done using the system, and the results showed that the system had good testing capability.