Abstract: Starting late,study on high performance oil base drilling fluid in China lags way behind that in overseas countries.Domestic oil base drilling fluid,with shortcomings like low yield value and poor rheologic property,can not fully meet the requirements of wellbore stabilization and hole cleaning in the drilling of shale horizontal wells.In view of the above-mentioned questions,by learning from advanced oversea technology,high performance oil base drilling fluid(HPOBM) for shale horizontal wells was designed.Then,a new HPOBM formula was studied after some key materials were developed,and its comprehensive performance was evaluated systematically.The test result showed that the technological parameters of this formula could compare with those of the similar oversea HPOBM.The new oil base drilling fluid formula was used successfully in shale gas horizontal well of Pengye 2HF,and this well set a new record of the longest horizontal well section and horizontal displacement in China.So,the development and application of this technology is of great significance in bringing the manufacture of domestic HPOBM to a higher level.