Abstract: Data is the foundation of all intelligence and optimization. Affected by mechanical structure of bottom hole assembly (BHA) and working characteristics of downhole motor, reliable data at bit position cannot be obtained by original measuring subs which are installed upstream of the screw. It leads to serious ambiguity and bias in data samples of basic theory research and intelligent model training. Application risks of intelligent decision and controlling are unpredictable. Therefore, digital bit, which can be installed in bit without any changes of BHA structure, was developed by oil company to provide the data foundation of theory research、ROP increment and decision optimization. In this paper, the technical state、application scenarios and development tendency are discussed.