The invention relates to an air conditioning system which can transmit sea cold along underground water-bearing layer, comprising a water source, a water feeding pump, a water processor, water filling pump, two stop valves, two heat exchangers, a pump tube, a reflux branch tube, an air cooling processor, a purifying tank, a butterfly valve, a water pump, a reflux pump, a coast protector, a filling tube, and a porous tip. The invention uses tap water to absorb the sea cold via a heat exchanger, and uses an underground second water-bearing layer as the coolant channel to transmit cold to object area. The invention can keep enough water content in underground water-bearing layer via continuous water filling method to avoid ground sink, while the invention can save energy, reduce cost, and protect environment.