<p>A new steel pipe detection system with a high lift-off detachable enhanced magnetic moment with targeted magnetic core extension and magnetic field focusing probe and its electronic control centre has been proposed to detect in-service steel pipe damage. The system adopts a parabolic arc-arm coil structure to increase the magnetic moment and achieve the target magnetic core extension, supplemented by a targeted compensation coil for targeted magnetic field focusing. We have also developed a supporting circuit control centre to further expand the detection magnitude of data collection. Experimental verification was conducted on 20# steel pipes under various conditions, including different defect scales, defect circumferential positions, pipe wall thicknesses, and operating environments such as thick cladding under extreme conditions. The results showed that the system achieved a probe lift-off height of up to 4.1 times the pipe diameter, detected defects throughout the entire wall thickness, and could discriminate defect severity, increasing the maximum effective detection distance by 28.23% compared to the previous generation system, it can assist in detection of pipelines with ultra-thick cladding or deeper burial dimensions under extreme operating conditions such as high temperature and deep cold. This study discovered the magnetic moment enhancement effect of targeted magnetic core extension and, based on it, optimised the design of the detection end structure. Combined with its corresponding signal characterisation form and circuit control instrument, it contributes to a new way of in-service pipe detection.</p>