The developed countries have being experienced an emergence of a growing aging population. Home caring robot is an excellent candidate capable of supporting such an aging society. In the paper, a robot is designed to move up and-down stairs to provide service for the elders. The robot consists of a main body for moving, a front arm and a rear arm for moving up and down stairs. The main body is equipped with two brushless dc motors (BLDCMs) and their drives for locomotion, worm gears for torque amplification, two dc motors to control two arms. The robot is equipped with roller chains attached with rubber blocks used to generate friction with ground and stairs for moving. The distance between any two rubber blocks is properly arranged to fix the stair brink. The moving direction of the robot is steered based on the speed difference of two BLDCMs and the information from ultrasonic sensors.