In view of high temperature and high pressure operating environment, brazed bodies of thrust chamber, generator and vernier engine of modern liquid rocket engines adopt corrugated plate and milled groove structures. The brazing and diffusion welding quality directly affects the compressive strength and cooling effect of the product. Therefore, the testing of brazing and diffusion welding quality is of great importance. The paper discussed the feasibility and existing problems of testing brazing and diffusion welding quality of corrugated plate and milled groove structures by various NDT techniques. Testability of different methods was also defined.