Abstract: When inspection robot negotiates obstacles autonomously,the mass eccentricity will result in tilt of the robot body.A centroid adjustment method is presented which can maintain the horizontal pose robot body when one arm is hung on the overhead ground lines.The balance weight is moved by the servo motor according to the angle of inclination between the inspection robot body and the horizontal plane,which can be checked by the obliquitous sensor,so that the centroid position of inspection robot is concentrated on the arm that is hung on the overhead ground lines.Because the body of inspection robot is kept in horizontal pose,the other arm can accomplish corresponding task for attaching to or detaching from the overhead ground lines.Finally,the simulation tests show that the centroid adjustment method is feasible.