The invention provides a doubly-communicated water cyclic purification system for an aquaculture pond and a water cyclic purification method. The purification system comprises an oxygenation tank, anozonator and a cooling water tank; the oxygenation tank is connected with the aquaculture pond through a first pipeline, two ends of the first pipeline are located at bottoms of the oxygenation tank and the aquaculture pond respectively, and an aeration disc and a filter are arranged in the oxygenation tank from bottom to top; the ozone output end of the ozonator is connected with the bottom of the oxygenation tank through an ozone conveying pipeline; the cooling water tank is connected with the oxygenation tank through a second pipeline, a water pump is arranged on the second pipeline and thewater inlet end is located between the liquid level of the oxygenation tank and the filter, the cooling water tank is connected with the aquaculture pond through a backwater pipeline, and the water outlet of the backwater pipeline is formed on the middle-upper part of the aquaculture pond, wherein the oxygenation tank is located on one side of the aquaculture pond and has the same height as the aquaculture pond, and the whole cooling water tank is located above the liquid level of the oxygenation tank. According to the doubly-communicated water cyclic purification system for the aquaculture pond and the water cyclic purification method, the aquaculture water environment is improved, and the whole process is energy-saving and environmentally friendly at the same time.