A cooling system for a vehicle may include a cooling water temperature sensor, a cooling circulation fluid passage including first, second and third fluid passages, wherein the cooling water exhausted from the engine may be branched into the first fluid passage provided with a heater core, the second fluid passage provided with a radiator, and the third fluid passage provided with an exhaust heat recovery apparatus, a fluid flow adjusting valve provided on a point at which the cooling water passing through the cooling water temperature sensor may be branched into the first fluid passage to the third fluid passage to adjust a flow of the cooling water, and a controlling part controlling the first fluid passage to the third fluid passage to be selectively opened or closed by operating the fluid flow adjusting valve depending on the temperature of the cooling water, in a heating mode and a non-heating mode.