Abstract: With the characteristics of high reliability, high quantitative precision, low cost and high efficiency, the time of flight diffraction (TOFD) technique is widely applied to many aspects such as boiler, pressure vessel and pressure piping inspection in China since 2001. In this paper, the application of TOFD technique in China is introduced and discussed. The principle of TOFD was introduced, in which the advantages and disadvantages were pointed out. Then, the application and the development of the technique are discussed in detail. Compared with other ultrasonic techniques, the TOFD is fit for pressure vessels and boils much more. Finally, the existing standards and development trend of standards about TOFD in China are enumerated. Furthermore, we believe that homemade research on key technique and equipment is the important development direction in future in China.