The invention provides a cooling system and a cooling method. The cooling system is used for an air conditioner and comprises a water supply component, a modular cooling pipe which is connected with the water supply component in series, and a condensation water pipeline which is connected with the water supply component in a pipeline manner and is used for draining cooling liquid into the water supply component to cool fluid when the temperature of the fluid in the modular cooling pipe is too high. By means of the technical scheme, the cooling system structure is simplified, the refrigerating capacity of low-temperature condensation water is fully utilized, the heat dissipation capacity of the cooling system to an electrical control module is improved, and the energy consumption is reduced.