Abstract: The analysis of slope stability is always a common problem. it is difficult in the engineering construction. Two kinds of software, namedSLIDE and FLAC, are often used to simulate the state of the slope and calculate the slope safety factor. To compare the difference between these two software in the analysis of slope stability, these two software were used to analyze the slope stability of Guangongao hydropower station in Fujian province and solve the safety factor. During the simulations, we found that the SLIDE software requires to set the shape of the sliding surface and the range of center of the sliding surface. Different sliding surface morphology and range of center result in different calculated safety factor, which makes SLIDE greatly influenced by subjectivity and leads to the error increases. We also found that centralized search box has little effect on the calculated safety factor.. Unlike the SLIDE, FLAC considered the stress-strain relationship of rock. The failure surface can be found through the material properities simulation avoid setting failure surface. The sliding surface set with FLAC is more reasonable than that with SLIDE. In addition, the safety factor calculated with strength reduction method is more accurate. The results would give some guidance to the similar engineering and provide assistance for insiders who use these two kinds of software.