A vehicle battery cooling system is provided and includes an air conditioning device including a compressor, a condenser, an evaporator, and a first expansion valve that are connected via a refrigerant line and circulating a refrigerant to reduce temperature within the vehicle. An electric unit cooling device includes an electric unit radiator and a water pump connected with a cooling line and circulates cooling water to cool a motor and an electric unit. A battery module connects with the cooling device via a battery cooling line. A chiller connects with the refrigerant line via a first connection line and the battery cooling line via a second connection line, and adjusts cooling water temperature by selectively heat-exchanging the cooling water and the refrigerant. Another water pump is disposed on the battery cooling line between the battery module and the chiller and a heater is disposed on the battery cooling line between the other water pump and the battery module.