This paper will review the research and development of eddy current NDT testing, condition monitoring and the associated instruments, which the author has been closely involved over the past decade. Eddy current testing and imaging is firstly introduced, focusing on property measurement of porous metals and imaging liquid metals. Condition monitoring is then presented from fundamental aspects in the high voltage insulation diagnosis to applications in large-scale generators and power plants. Finally, the challenges we will face in these areas are summarised.