High altitude, short frost-free period and about 20m thick permafrost at 4000m above sea level are the characteristics in Qinghai area, where drilling is difficult because of the influence of flushing fluid and heat produced by high-speed rotary friction of drill pipe. Formation dissolution and collapsing occurred in the process of ice melting, and in addition to difficult polymer dissolution at low temperature, the rheology performance is affected. By improving the drilling tool joints and optimizing drilling fluid performance, construction difficulties were solved. The paper introduces the improvement of s and the flushing fluid technology.