The invention provides an automatic cleaning system for an air cooling outdoor unit of an air conditioning system, wherein the automatic cleaning system can reduce the power consumption and fully use condensed water. The automatic cleaning system for the air cooling outdoor unit of the air conditioning system comprises a condensed water storage tank; the condensed water storage tank is provided with a water inlet hole, a water outlet hole, a repair hole and a water leaking hole; a filter screen is arranged at the upper part of the condensed water storage tank; a water pump is arranged at the bottom of the condensed water storage tank, and is connected with a flushing mother pipe; the flushing mother pipe is connected with a flushing son pipe; the flushing son pipe is connected with a spraying row pipe; a nozzle is formed in the spraying row pipe; and a liquid level is arranged in the condensed water storage tank, and is connected with the water pump. The automatic cleaning system fully uses the condensed water of the air conditioning system for cleaning a condenser, improves the performance coefficient of the air conditioning system when reducing the temperature of outdoor air, and reaches a comprehensive energy saving rate of 4.2-8.5%. The condensed water storage tank adopts a stainless steel modular spliced water tank, so that the batch production is convenient, the popularization is facilitated, and the condensed water, frequently wasted, are fully used.