Abstract: To adjust tool face of BHA during coiled tubing drilling (CTD), an electric-hydraulic orienter (EHO) was designed after analyzing the method and principle of such adjustment. With a vector description of the space circular arc wellbore trajectory and with a consideration of structures of the orienter and the relevant adjustment techniques, the method of adjustment was established. In addition, the function model for displacement of the sliding nut and orientation of the tool surface was constructed. By using the newly developed adjustment method, the tool face angle could be adjusted precisely between 0°to 360° by controlling the reciprocating movement of the piston in one trip (0-110 mm). Research results showed that with the tool face angle modified between 0° and 360 °, the movement displacement of the sliding nut and the adjustment of tool face angle was in a "broken line" relationship. In each "line" of the two inclined straight line segments, the movement displacement of the sliding nut increases linearly with the change of the tool face angle adjustment. The tool face adjustment method of the new EHO was determined to be feasible. The newly developed EHO could effectively enhance drilling efficiency of CTD. In addition, the EHO with the tool face adjustment method would meet the requirements for CTD and would contribute to development of CTD in China.