In order to better adapt to the requirements of green exploration， promote the green development of geological drilling， and promote the progress of green exploration， optimization experiment of environment-friendly drilling fluid additives and systems was carried out with the development of the environment-friendly drilling fluid system suitable for Qinghai coal measures complex strata through indoor experimental research focused on whether the environment-friendly drilling fluid system to be developed can meet the requirements of environmental protection and drilling engineering； and production test was successfully carried out in HF-4 borehole of the Muli Coalfield comprehensive engineering geological exploration project. Indoor experimental study and field application showed that the developed environment-friendly drilling fluid reaches the national environmental protection discharge standard for biotoxicity with EC₅₀ ≥ 30000 mg/L， has solved the technical problems of hole wall instability in complex Qinghai Coal Measures， formed an environment-friendly drilling fluid system suitable for Qinghai coal measures complex formation， and achieved good economic and social benefits， indicating that the technical achievement has a good application prospect.