Abstract: This article introduces a new ultrasonic tandem scanning method for rails:phased array tandem scanning. Compared with conventional ultrasonic tandem scanning method, this detection method has the characteristics of high coverage, high efficiency, simple operation, rich and intuitive display of defect information and so on. Through the tandem scanning of the rail aluminothermic weld test block (YN-1 type), the feasibility of the scanning method in rail weld inspection was verified.