Abstract: The mechanics characteristics of the single stabilizer BHA in directional well was thoroughly analyzed based on the theory of vertical-lateral bending, and the building, holding and dropping BHAs of single stabilizer were selected according to the analysis. Its characteristics were described from four aspects, and the relationship between the stabilizer OD, WOB, hole inclination and bit deviating force was also illustrated. The influence of drill collar to the performance of single stabilizer BHA was further investigated. The selected BHAs were used in over 200 directional and cluster wells in Longdong and Shanbei, and remarkable improvement on drilling performance was found, moreover, it met the requirements of trajectory control in directional well, and realized the goal of safe and fast drilling.