In the paper, a robot is designed to move up-and-down stairs for providing service. This robot consists of a main body, actuating system, roller chains, a front arm and a rear arm for assisting in moving up and down stairs. The actuating system includes two brushless DC motors for locomotion, two worm gears for torque magnification, and two DC motors to control arms. A DSP-based board acts as control center. Some rubber blocks attached to the roller chains are used to generate friction with ground and stairs for moving. A fuzzy logic controller integrates the outputs of DC bus current sensor and an inclinometer to steer the robot. Two walking experiments of moving up and down stairs with the rise/depth of 120/400 mm and 175/280 mm are shown in the taped pictures from videos to verify the proposed design.