Abstract:The grey forecasting models for deformation monitoring are divided into three types: the traditional GM(1,1) model and its improved models, the non-homogeneous grey model, and the GM(1,1) power model and its improved models. We adopt the Origin fitting functions Exp2PModl, Exponential, and SRichards2 as the alternative methods of the three types of grey forecasting models. Based on the theoretical research and example validation, we compare and analyze the three types of grey forecasting models and their alternative methods. The results show that there are significant differences among the three types of grey forecasting models in terms of the fitting function, the presence or absence of limit values, the suitability for equidistant or non-equidistant modeling, and the scope of applicability; it is necessary to select a suitable grey forecasting model according to the characteristics of deformation monitoring data. Compared with the three types of grey forecasting models, the Origin fitting function is more advantageous in parameter solving and requirements on modeling data; it can obtain comparable or even higher fitting or prediction accuracy, which can be completely used in deformation monitoring instead of grey forecasting models, except for special optimization objectives that need to be realized by programming.