Abstract: At present, the early detection of high temperature hydrogen attack(HTHA) was one of problems needed be solved urgently for petrochemical enterprises who wanted to achieve the equipments running for longer circulating. Standard specimens comprising the HTHA were designed and produced. The dependency between the degree of HTHA and the acoustic parameter of ultrasonic was measured and analyzed; The degree of HTHA was characterized and evaluated through the methods of metallographic examination and hardness test; It would accumulate data in order to establish the rapid-diagnosis methods of the HTHA in early stage.