Abstract: Circle sliced method,with its simple principle and brief formula,is complex in calculation process,the searching of potential slip surface also has uncertainty.So the authors have proposed a method of searching the most possible slip surface. Further more, an analytical solution of Fellenius method was also produced. On the other wise, in consider of many sliding surfaces with high back cliff and nearly circle in the lower potion, the authors made some revisions for the analytical formula to suitable for the situation. The method is used to calculated the factor of safety of a high loess slope of a coal mine in Binxian County,Shaanxi Province, China.The results are more close to the actual situation than with circle sliced method.