Nansi Lake, a typical shallow and macrophyte-dominated lake in south Shandong Province, China, has a total surface area of 1,266 km² and is the largest and most important freshwater reservoir in northern China for the eastern route of the South-North Water Diversion (SNWD) project, in which the water in Yangtze River will be transported more than 1,100 km from Yangzhou to Tianjin and Beijing. A water-level fluctuating zone (WLFZ) near Nansi Lake will be formed when the SNWD project begins to transport water flowing through the lake. Phosphorus fractions and adsorption-release characterization for soil samples from four typical lands (reed, wood, maize, and soybean) were conducted to investigate soil phosphorus stability. In addition, a soil submerged experiment was performed to simulate phosphorus release under submerged conditions. Phosphorus adsorption-desorption equilibrium concentrations (C_EPC) of four lands were 0.006, 0.089, 0 .110, and 0.287 mg L^-1, respectively, which means that maize, soybean, and woodland had higher potentials than reed land for phosphorus releasing to the overlaying water. Submerged experiment results showed that the quantities of p hosphorus released from reed, wood, maize, and soybean soils were -0.14, 0.06, 0.12, and 0.97 mg kg^-1, respectively. Soils in the reed land adsorbed phosphorus from overlying water, but the other soils released phosphorus into the water. Thus, in order to decrease the phosphorus releasing quantity from the wood, soybean, and maize land under the conditions of submerged lands at water diversion time, the land uses of wood, soybean, and maize should be switched to land for planting reed.