Abstract: In-service inspection of nuclear power plant is the important way for keeping safety operation. There is specific requirement of nuclear safety rule of law and guide to pre-service inspection and in-service inspection of nuclear safety equipment. History of in-service nondestructive testing development in nuclear power plant was reviewed, the relative application status of ISI code and standard was introduced, the implementation status of performance demonstration of ISI technology between domestic and aboard nuclear power plant was summarized. Some suggestions for Chinese independent development of ISI and performance demonstration were given.