A cooling water flow control device of a cooling system for a vehicle can shorten a warm-up time of a cooling water being supplied to an exhaust gas recirculation (EGR) cooler. The cooling water flow control device includes: the EGR cooler that cools an exhaust gas supplied to an intake system of an engine using cooling water and includes an EGR cooler outlet through which the cooling water is discharged; a water pump to circulate the cooling water to the EGR cooler and the engine at an engine startup; and a direct flow path connected to a vent hole formed in the engine to guide the cooling water from the vent hole to a downstream side of an EGR cooler outlet.