A system for controlling an air flow rate into a vehicle engine room may include a fan shroud in which a cooling fan including a fan motor and a fan blade is mounted, a radial portion which is provided in the fan shroud while corresponding to an operation area of the fan blade, including a shutter hub positioned to a center thereof and a plurality of radial units disposed to the shutter hub and including a plurality of radial shutters selectively unfolded from the shutter hub to external circumference directions or selectively folded to the shutter hub direction, and a radial unit operating portion unfolding the plurality of radial units from the shutter hub to the external circumference directions or folding the plurality of radial units to the shutter hub direction.