A roll control system improves stability in turning by actively controlling roll stiffness in accordance with traveling conditions of a vehicle. The active roll control system for a vehicle suspension includes a stabilizer bar of which the middle straight portion is fixed to a sub-frame by a mount bush and both ends are connected with a lower control arm by a stabilizer link to suppress roll of the vehicle body, in which a roll control mechanism is disposed between a lower end connecting portion of the stabilizer link and the lower control arm to increase roll stiffness by increasing a lever ratio of the stabilizer bar, if needed.