The Upgrading Project of Guiyang-Guangzhou High-Speed Railway marks China's first comprehensive upgrading of an operating high-speed railway.It is the first domestic project to implement speed raising and upgrading on a high-speed railway operating at speeds of 250 km/h or above without changing the major existing infrastructure.It is also the first high-speed railway project in China to upgrade its train control system from CTCS-2 to CTCS-3.Through the adaptability analysis of speed raising,this paper systematically proposes research ideas for upgrading the existing high-speed railway.Combined with the original design and existing operation status of Guiyang-Guangzhou High-speed Railway,it scientifically demonstrates the feasibility of speed raising and upgrading within the context of the existing infrastructure,and proposes solutions to the situation that the parameters and indicators of existing equipment fall short of current specifications.The findings can provide reference for similar high-speed railway reconstruction projects.