Abstract: The lead sealing is a common way of connecting high-voltage cables. Due to the interference of external heat-shrinkable sleeves and waterproof tapes, conventional inspection methods are difficult to inspect the internal lead seal connection status. Simulate onsite use conditions and process defects to prepare high-voltage cable lead seal samples. Carry out inspection experiments based on alternating current field measurement(ACFM)technology at the same time. Testing results shows that ACFM can penetrate the protective layer to detect the surface cracking defects of the lead seal. The detection sensitivity and resolution are better than other methods. The detection direction should be considered when detecting because the detection result will be affected by the angle of the probe.