Abstract: This paper is proposed to establish a criterion for prevention of groundwater buoyancy on construction design,and give basis for site investigations.Further,with the formula for prevention of groundwater level up-floating,calculating and explaining the meaning of each factor of the most adverse conditions,and recommending technical basis of combination effects for groundwater level.According to the principle of hydraulic continuity,and on other relevant engineering technical conditions,commenting the risk of reduction of groundwater buoyancy on foundations built under an inferior seepage stratum,where the value for construction gravity should be chosen as a resistance during the analysis of foundation up-floating.In addition,the groundwater level parameters for prevention of up-floating could be relevant in other functions.