According to the deep formation characteristics of west block of Mahuangshan, high temperature-resisting drilling fluid system was selected in lab and study was made on the performance optimization. The high temperature tolerance and anti-contamination abilities were improved, crosslinking reaction between SPC-220 and sulfonating agent was introduced for improve the ability of anti-salt pollution. The field application of Ningshen well 1 proved that the property of the high temperature-resisting drilling fluid system is stable and has played important role in the construction of complex formations.