Abstract: The operation of offshore ultra-high temperature and pressure wells is difficult due to the characteristics of ultra-high formation temperature, ultra-high formation pressure and the extremely narrow pressure window. Coring in ultra-high temperature and pressure well sections involves high risks such as well control and lost circulation, so it is a very difficult operation. This paper analyzes the technical difficulties of coring in the ultra-high temperature and high pressure well section, so as to study the coring barrel, drilling tool assembly, drilling parameter optimization, well control measures and leakage prevention measures, and puts forward the improvement plan of the coring barrel, recommended drilling tool assembly and drilling parameters, well control measures and leakage prevention measures, which have been applied in the practice of Well LD13 with the ultra-high temperature and high pressure for the first time. The reconstructed coring barrel was used in the construction, which controlled the well control risk, avoided lost circulation, and finally achieved 100% coring recovery. The coring operation in the offshore ultra-high temperature and high pressure well section of South China Sea was successfully completed. The application effect is obvious, which can provide effective reference for coring in the offshore ultra-high temperature and high pressure well section.