Closed water test nondestructive testing system and method

The invention relates to the technical field of water leakage detection, in particular to a closed water test nondestructive testing system and method. The closed water test nondestructive detection system comprises detection equipment and a prefabricated pipeline, the detection equipment comprises a base, an ultrasonic seat and an ultrasonic detector, the ultrasonic seat is arranged at the bottom of the base, and the ultrasonic detector is rotationally connected with the ultrasonic seat; the prefabricated pipeline comprises a pipe body and a plurality of detection units arranged in the axial direction of the pipe body, each detection unit comprises a first magnet, a second magnet and reflection pieces, the first magnets are arranged at the top of the pipe body in the axial direction of the pipe body, the second magnets are arranged at the bottom of the pipe body in the radial direction of the pipe body, and the reflection pieces are arranged on the two sides of the second magnets. And a preset angle is forme