A u-MDPS (United Motor Driven Power Steering) system includes one MDPS motor, one MDPS ECU that assists steering force using power of the MDPS motor, and has a logic implementing tilting-up/down and telescopic movement, and a multi-function generator that switches a power transmission path of the MDPS motor to the steering path for assisting a steering force, the tilt path for tilting up/down a column tube, or the telescopic path for facilitating a telescopic movement of the column tube. The multi-function generator may include a motor power converting unit, a motor power transmitting unit and a tilt•telescopic motion unit. The tilt•telescopic motion unit further includes an electromagnetic clutch, which makes it possible to implement fail-safety function by switching to a lock-manual mode of one MDPS motor.