It is necessary to predict and control deflection and stress in continuous beam bridge construction. SCGMmv (1, h) is a multifactor forecasting model for a time series based on the mean values. For a specific project, by using the association between deflection and stress, the SCGMmv (1, h) forecasting model is employed to obtain forecast values of deflection and stress, which are compared with the forecast values of the GM (1,1) prediction model. The results show that the SCGMmv (1, h) multifactor forecasting model is feasible and effective for deflection and stress prediction in continuous beam bridge construction.