Foundation stability calculation is an important step to ensure the safety of the structure connecting shore of the high piled wharf，and the choice of foundation stability calculation method is crucial. To solve this problem，we choose the Swedish slices method and composite sliding surface method for the comparison of resistance division coefficient calculation and propose a treatment scheme for weak interlayer. At the same time，based on the original design，the sensitivity analysis of the key parameters of the weak interlayers，such as cohesion，internal friction angle，and thickness，and the correlation analysis of the coefficient of frictional resistance，are combined with the two methods. The results show that two methods should be used for the foundation stability calculations；under the same rate of change，the influence of the internal friction angle resistance component coefficient is significantly higher than the influence of the cohesion force；the minimum values of the fractional coefficients calculated by the two methods are highly correlated. The conclusion can provide a reference for the foundation stability calculations under similar conditions.