Based on the exponential trend model

the Kalman filter model is applied to forecasting displacement values at observation point in Lianziya hazardous rock mass GA. At first

nonlinear exponential trend model is linearized into linear model; and linearized model parameters are obtained using the linear least square method; the linearized model parameters are regarded as state vectors containing dynamic noises to erect Kalman filter model. On the basis of Kalman filter model

the displacement values of the hazardous rock mass are forecasted. An example of calculation shows that the forecast error is little and the forecast effect is good using Kalman filter model to forecast the displacement values of the hazardous rock mass .