Abstract: In view of the long-term rolling contact between the railway track and the locomotive wheel, stress fatigue cracks are easily generated, which threatens the safe operation of the railway. Based on the alternating current field measurement, this paper designs and develops a set of detection software-portable chassis-detection probe to meet the requirements for the detection of the railway track. The integrated alternating current field measurement detection system detects the artificial defects and natural defects on the rails respectively. The test results show that alternating current field measurement defect detection system can realize the real-time detection of the defects on the rails, and can preliminarily judge the position and size of the defect. The obtained results can provide some support for the railway safety assessment of China.