Abstract: It is necessary to detect the defects of Rod Cluster Control Assembly used in nuclear power plant reactors to ensure the successful implementation in service inspection and reduce the cost of nondestructive testing. The ultrasonic probe for Rod Cluster Control Assembly (RCCA) inspection is developed independently. This paper describes the development process of ultrasonic probe about 15MHz-Φ4mm-H4mm-OD6mm. The development process is described in detail in three aspects: piezoelectric wafer, acoustic les and backing. The performance of the ultrasonic probe was tested. The number of pulse cycles is 1.5 weeks and the frequency band width is 105%. The defect test results are clearly visible, and the sensitivity and signal-to-noise ratio meet the inspection requirements in the simulation and inspection of the ultrasonic probe. It can completely replace the imported products with domestic ones.