A cooling system for an engine, may include a low temperature radiator; an intercooler installed to receive a coolant cooled from the low temperature radiator and restore the coolant to the low temperature radiator again after heat exchange; a water pump installed to supply the coolant to the intercooler by pumping the coolant cooled from the low temperature radiator; a motorized supercharger installed to receive the coolant from the intercooler; and a reservoir installed to store the coolant passing through the motorized supercharger and deliver the coolant to a coolant line between the low temperature radiator and the water pump.