The purpose of this article was to investigate the influence of uncertain soil parameters on slope stability problems using the probability method. The most important soil instability is probably the inherent spatial variability of soil properties and its influence on slope safety factors. The probability method is recognized for its validity both in practice and academic research. This method of geotechnical risk management involves uncertain parameters. In this study, randomly selected uncertain parameters were combined with traditional analysis using Bishop’s simple methodology and Monte Carlo simulation. The minimum safety factor and critical slip surface of the slope stability were analyzed by Bishop’s simple method. The influence of uncertain soil parameters was analyzed by the back analysis method with Monte Carlo simulation. The calculation was controlled by a critical slip surface, and the safety factor was equal to 1. The results of the analysis show the minimum safety factor and the significant slippery surface of slope stability with the original soil strength parameters. The new soil strength parameters were recommended by Monte Carlo simulation that was used for improving the soil strength parameters in construction. In addition, probability analysis can identify an insufficient understanding of groundwater level distribution and that the assumption of a uniform distribution increases the probability of failure. Governments can use the results of water level analysis in flood warnings and flood management projects to reduce risks to life and property.