The invention relates to a phase-change energy-storage air-conditioning system. The phase-change energy-storage air-conditioning system structurally comprises a cooling tower, a cooling water circulating pump set, a refrigeration host, a terminal load, a chilled water circulating pump set and a cold-storage circulating system, wherein the refrigeration host comprises a condenser and an evaporator, and the cold-storage circulating system comprises a cold-storage tank, a variable-frequency water pump and a plurality of electric valves. The phase-change energy-storage air-conditioning system has the advantages that multiple kinds of cold-storage and cold-discharge modes can be transformed flexibly by means of controlling the electric valves to open and close, so that the refrigeration host is kept at the optimal energy efficiency ratio state to work, an optimal energy-saving effect is achieved, the 'power peak shaving and valley filling' performance is optimized, most stable chilled water outlet temperature can be obtained and the refrigeration performance is improved; meanwhile, the capacity of the refrigeration host can be expanded, the integral installed capacity and power supply equipment of the system can be decreased substantially, and a huge sum of initial installation fees can be saved; additionally, the phase-change energy-storage air-conditioning system is simple in structure, small in occupied space and quite convenient to apply.