Soil organic matter is a soil carbon pool, and its content and dynamics is very important to global C cycling, soil fertility, and soil quality. SOM models can simulate soil organic matter dynamics and predict its content, especially for which some of data are difficult or impossible to obtain by experiential hypotheses and existing data. Therefore, SOM models have become the most important quantitative means to study SOM decomposition and accumulation, and can help us to identify the mechanism about SOM dynamics. SOM models can also predict CO2 emission and plant growth, and evaluate agricultural management practices. Several SOM models, especially RothC model and CENTURY model, were summarized and analyzed in this paper.