The large bedded slopes are the common engineering geology in mountain areas. In this paper, the influence factors, including the gradients, slope length, thickness of slide body, of the large bedded slopes were analyzed. The influence laws of the toe segment slippage length of the factors were obtained and the computing formulas of the toe segment slippage length were presented. The computing formulas were validated by the data of field survey. The results indicated that the toe segment slippage length which were determined by the slope length (L), thickness of slide body (H) and slope gradient (α) were according with the field survey and had the better safety coefficients.