Scientific ultra deep well is an important part of energy development strategy and the "transparent earth" project in China. As a key part of scientific ultra deep well, the drill string provides a guarantee for the safe and successful implementation of deep exploration engineering with its optimized configuration. Aiming at scientific selection of drill string for the demand of myriametre drilling depth, and considering the overall strength, sealing performance and continuous stability of drill string in use, this paper discusses seven key technologies based on analysis of technical challenges faced by the drill string in ultra deep well, such as pipe technology of high strength-to-weight ratio, composite drill string technology, joint optimization technology, drill pipe manufacturing technology, coating protection technology, dynamic analysis and intelligent drill string，and proposes the optimized configuration solution of drill string for myriametre scientific drilling. At the same time, the development trend of drill string is analyzed. It defines the research direction of the drill string for myriametre scientific well.

drill string configuration  /  scientific drilling  /  myriametre working condition  /  key technology