Abstract：It is a key problem to select the initial prediction time with Verhulst inverse function model in landslide study. Generally，there is a problem of selecting by quantitative calculation method in that the independent variable of logarithm function in the model may be negative. The predicted data of accumulated displacement and relative displacement are calculated with all ，and all predicted -curves are formed. The initial prediction time can be selected with analyzing the predicted curves and monitoring curves. The selecting principles are as follows：(1) the predicted displacements can be calculated on points n and n+1 of the monitoring list；(2) the curve configuration of predicted accumulated displacements is similar to the monitoring curve；and (3) the dispersion between the monitoring relative displacement and its predicted value on the point n is the least. The experimental results of several groups of measured data show that the precision of critical sliding time can be obtained within one time interval；and the method to choose is effective.
