Abstract: It is of high risks to build super-long tunnels in the area with high ground temperature which brings great challenges to the tunnel construction and operation. Based on the Gaoligongshan tunnel on Dali-Ruili railway,the longest under construction in China, the key techniques for comprehensive control of heat harm of the superlong tunnel are studied, the standard of thermal environment control and the reasonable area of heat harm control are determined, a series of combined cooling methods like ventilation, refrigeration and geothermal water treatment are designed, and the supporting system of tunnel structure and anti-cracking measures under high ground temperature are proposed; the new construction materials suitable for high temperature environment are developed by indoor model test; a three-dimensional unsteady heat transfer model is established according to the theory of heat transfer,the temperature field under tunnel operation environment is simulated, and the cooling countermeasures of segmented longitudinal ventilation by using ventilation shafts during tunnel operation are worked out.