Abstract: In view of complex structures and reservoir media in "Deep Underground Engineering", which includes deep burial, high formation pressure and temperature, and other complicated conditions, Sinopec has carried out key research on technologies such as deep and ultra-deep oil and gas testing, ultra-high temperature and high-pressure bottom hole assembly (BHA), surface testing, oil and gas well testing engineering design of narrow safety window, and well completion testing fluid, etc. Sinopec successfully completed the testing construction of more than 100 oil and gas wells with depth more than 8000 m, and initially formed the initial key technologies and supporting equipment for oil and gas testing in “Deep Underground Engineering”, which strongly supported the exploration and production of deep and ultra-deep oil and gas resources in the Tarim Basin, Sichuan Basin, and Junggar Basin. The key technologies of oil and gas testing in Sinopec’s “Deep Underground Engineering” were summarized, and the challenges in oil and gas testing technologies faced by Sinopec’s “Deep Underground Engineering” during exploration from 9000 m to deeper than 10000 m were analyzed. Technical prospects were put forward for the design of extra-deep high-temperature and high-pressure oil and gas testing engineering, extra-deep high-temperature and high-pressure oil and gas testing completion technology, ground automation testing, and high-performance oil and gas testing tools, etc. The overview and prospect of these technologies are of reference significance for the construction of a more mature, professional, safe, and efficient oil and gas testing technology system, in order to help achieve greater breakthroughs in the exploration and development of deep and ultra-deep oil and gas reservoirs.