对影响长江南京段防洪堤结构稳定的不确定性作了初步分析，提出了防洪堤工程失稳风险计算的数学模型．借助于ＭｏｎｔｅＣａｒｌｏ方法，具体计算了目前长江南京段防洪堤工程失稳风险的大小．计算表明，目前长江南京段防洪堤发生边坡失稳的风险度为１１５％，发生渗透变形的风险度为０６３％． A preliminary analysis is made of the uncertainties affecting the structural stability of the flood control dike in the Nanjing section of the Yangtze River and a mathematic model for calculating the risk of the instability of the flood control dike is proposed. With Monte Carlo method, the magnitude of the instability of the current flood control dike in Nanjing section of the Yangtze River is calculated. The calculation shows that the risk of slope instability of the bank levee in Nanjing section is 115% at present, and the risk of infiltration deformation is 0.63%.