The invention relates to a steam generator heat-transfer pipe ultrasonic inspection system. The system comprises a probe assembly, a probe rotation device, a probe gate device and a conduit. The probe assembly comprises a probe clamper, several probes on the probe clamper and an ultrasonic cable connected to the ultrasonic probes. The probe rotation device comprises a sliding brush and a motor. The sliding brush comprises a motion part and a fixed part. An ultrasonic cable is partly connected to the motion part of the sliding brush. A motor output shaft is partly connected to the motion part of the sliding brush and drives the probe assembly to integrally move. The probe gate device is provided with a water supply pipe connector communicated with the interior of the probe gate device. The conduit goes through the probe gate device and is connected to the probe rotation device. Several cables and a water supply pipe are arranged in the conduit. One end of the cable is respectively connected to the fixed part of the sliding brush and the motor. One end of the water supply pipe is connected to the water supply pipe connector. The system realizes regular examination of a steam generator heat-transfer pipe matrix metal material and especially is a water immersion ultrasonic inspection system for detecting a pipe expanding transition region of a heat-transfer pipe and a pipe plate.