The present invention discloses a window blind system, comprising a shading arrangement and an alternating hanging device vertically extended downwardly to support a plurality of slats in position, wherein a predetermined portion of the slats are both supported by the first shading arrangement and the alternating hanging device, so that by operating the alternating hanging device, the predetermined portion of the slats supported by the alternating hanging device are capable of being displaced with respect to the remaining slats thus creating a varying shading effect.