It has been a difficult problem to make up drilling fluid with stable performance under saltwater condition to keep borehole wall stability in the drilling construction in Gobi of Xinjiang. By the selection of drilling fluid materials and the test studies in different work areas, MBM-GTQ saltwater drilling fluid system was determined for use with good application effects for deep hole construction and accident treatment in intensily altered strata in Pobei Cu-Ni mine of Ruoqiang County. The practice proves that MBM-GTQ saltwater drilling fluid system is an effective scheme for the broken altered strata there.