In order to solve the problem in subsidence grading of soft soil, coupling model based on self-organizing feature map (SOM) and dynamic classification method was established in this study. This method provided a new way for ranking the foundation settlement in soft soil area. Correlation among influences was displayed by SOM simulation analysis. The independence among factors was ensured through weeding out individual factors. Dynamic classification method (DT) was applied to study subsidence grading and hierarchy was obtained in different classification data. The performance was compared with fuzzy synthesis assessment. The results showed that the coupling model had a good grading effect.