In order to solve the problems such as alkaline water waste and low comprehensive utilization during the process of washing out salt and decreasing alkali on saline-alkaline land, in respect to characteristics of the technique of washing out salt and decreasing alkali on saline-alkaline land, an ecologically engineered cultivation system of saline-alkali pond is designed. The system consists of lifted field, ditch, reservoir and aquaculture pond, with area ratio of 10:1:2:4. In the system, the bottom of the lifted field is laid with perforated pipe which connects with the reservoir, and the reservoir provides supplementary aquaculture water for the aquaculture pond. In the case of 3 000 m3/d of irrigation amount, the test results of soil and water quality of the system indicate that the salinity, chloride concentration and electrical conductivity of the water in the reservoir are much higher than those in the aquaculture pond and drainage ditch. The pH value of reservoir and aquaculture pond is significantly higher than that of the drainage ditch and the reservoir can effectively collect the saline-alkaline water in the process of washing out salt and decreasing alkali; pH and salinity are stable in the lifted field and there was no return of salt or alkali; the total nitrogen of aquaculture water in the ecologically engineered cultivation system of saline-alkaline pond is less than 4mg/L, and the total phosphorus is less than 1.3mg/L; the permanganate index is gradually decreasing, which is in line with the cultivation demand. The study shows that in comparison with traditional technique of washing out salt and decreasing alkali, the ecologically engineered cultivation system of saline-alkaline pond improves the circulation of irrigation water by 2.2 to 3 times, reduces nitrogen and phosphorus emissions, and has obvious effect of water saving and emission reduction.