To ensure ZK1122 open hole construction, low solid mud was used in common formation with proper lubricant to reduce friction resistance; strong inhibitor was used to maintain the borehole wall stability in water sensitive formation; weighted mud was used in special stress formation. And according to the different formation and different construction depth, different bottom hole assembly was selected. Thick core barrel, ladder bit with long matrix and with more hole reamer and centralizer ensure construction safety and efficiency. By the strict drilling regulation and site management, deep open hole drilling construction in complex formation was fulfilled.