In order to increase food supply and suppress the ecological degradation, the saline-alkaline land surrounded the Lake Chagan will be developed into the largest irrigated area-Songyuan Irrigation area, in the Songhuajiang-Nenjiang(Songnen) Plain. The area will be 2.84×10⁷ km². The proposed irrigated area is located in the center of saline-alkaline region of the plain. The important objectives include new rice fields, improving the existing dry land of low yields, and recovering grassland and wetland. The drained water from the irrigation area is saline-alkaline water, while the Lake Chagan is a light alkaline lake, the largest lake in the Songnen Plain, and a national natural protection zone. The plants under protection include Phragmites and Suaeda glauca (Bunge), and the animals under protection include Ciconia, Grus leucogeranus, Gruiformes, Aquila chrysaetos, etc. Most birds in the region belong to the first class national protected animals or endangered species. Therefore, the lake is an important base for the biological species and plays an important environmental function in accommodating local climate. In this area, the ecological systems have been seriously degraded, so that some of the land has become the alkaline deserts. Since the Lake Chagan is a conflux center for the ground and surface water, if the tailing water of the irrigation engineering is pumped into the lake directly, the lake biological system would be in serious aftermath. Thus the key issue is how to avoid the ecological risk that the development the irrigation area might bring to the Lake Chagan. For getting both the benefits of protecting the lake biological system and developing the saline-alkaline land, this paper, based on analyses of the risks, has designed five wetland disposal systems as the transition area to deal with the alkaline tailing water. First of all, through degrading and precipitating of the pollutants, the pH of the tailing water was decreased when it enters into the modeling water processing systems. If the salt contents need to be decreased, the tailing water should be mixed with the water deriving from the Songhua River. Only when the tailing water quality meets the standard, the water will be allowed to discharge into the lake. The hazard evaluation indicates that this utilization model would not only not damage the lake ecosystem, but also be conducive to the stabilization of the lake ecosystem. Furthermore, the utilization model could develop saline-alkaline region and promote social economic development in the area.