This paper introduces the safety service system of hydropower projects during operation stage in the perspective of the 3A hospitals. The definition, basic constitution and the main features of the 3A hospital in hydropower projects are discussed. The application and research of the key technologies during the health monitoring and evaluation for hydropower projects are stated. The basic framework of professional qualification rating and grading is also discussed. It is believed that the theory and method of the whole industrial chain and life cycle service in hydropower projects can be better established and improved in the perspective of 3A hospitals.