The invention discloses a dynamic double-cold-source pre-cooling energy-saving air conditioning system used for cooling a data center. The dynamic double-cold-source pre-cooling energy-saving air conditioning system comprises indoor unit structures such as evaporators, economical coil pipes, a draught fan, a water flow regulating valve, a water temperature sensor, a temperature-humidity sensor and internally-arranged plate-type condensation heat exchangers, and further comprises water pumps, a cooling tower and the like. According to the dynamic double-cold-source pre-cooling energy-saving air conditioning system, a cooling-capacity-variable compressor is adopted, the temperature of outlet water of the cooling tower is detected to control output of the compressor, the aim of simultaneously starting the economical coil pipes and the compressor for cooling under the high water temperature condition is achieved, and therefore natural cold sources are used to the maximum degree. The dynamic double-cold-source pre-cooling energy-saving air conditioning system is small in floor area and outdoor occupied space. If calculation is carried out according to the design at present, in the Shanghai area, the initial cost is reduced by more than 30% compared with a chilled water system, energy is saved by more than 36% relative to an air-cooled air conditioner, and the dynamic double-cold-source pre-cooling energy-saving air conditioning system powerfully completes and replaces a traditional scheme, has the wide adaptability and is remarkable in energy-saving effect.