Slope deformation and stability are influenced by geological conditions and external environmental factors and its displacement and deformation tendency may have such differences as complexity

variety and randomness of factors. Based on the analysis and summary of law of slope deformation and aimed at displacement-time curve of slope deformation presenting negative S-style characteristic with initial deformation

stability deformation and acceleration deformation in this paper

the variable-weight combination forecasting model with growth curve inverse function is built on the basis of measurement time series data of slope displacement. The contrastive analysis results with engineering application example show that the single forecasting method can approximately reflect deformation development trend of slope and have great error because the method based on the fixed model of known example

and the method which the paper presents can consider the advantages of different models and have application in deformation forecasting and instability warning of engineering project with high precision.