Drilling problems， such as melting permafrost strata， expansion and collapse of hole walls， less drilling depth， core taking difficulty， borehole freezing， are encountered in the process of drilling due to the characteristics of strata and the fact of the plateau permafrost environment of Dongchenggongma. Drilling equipment， drilling technology and drilling management was investigated with the focus on the effect of low-temperature drilling fluid properties on drilling process. Orthogonal experiment was conducted to compare the formulation of flushing fluid at -5℃ to select the optimum formulation with low temperature resistance， small heat dissipation coefficient， proper viscosity and low filtration loss， and it effectively solved the drilling problem in plateau permafrost strata. Field use in two boreholes of CZK031 and CZK4821 showed the hole wall was well protected by the drilling fluid， and no collapse and freezing accidents occurred， achieving good drilling effect. The research and application of low-temperature drilling fluid formulation can provide reference for drilling in plateau permafrost strata in other areas.