Abstract: It is difficult to conduct eddy current inspection on the horizontal steam generator for its  deep collector, numerous heat-exchanging tubes with many elbows and small bending radius and materials with poor uniformity. A horizontal steam generator eddy current testing system(C-SMART) for heat-exchanging tubes was developed, including mechanical positioning drive device, control system and control software, and eddy current data acquisition and analysis software. The system is with the characteristics of fast and accurate positioning, single tube calibration, high efficiency and so on. The system has significant economic and social benefits.