Plants in the wetlands are not only one of important parts of wetland ecosystem, but also a significant indicator of wetland ecosystem evolution. In recent decades, both quantity and quality of global wetlands have been decreasing at a higher speed caused by global warming and human activities. As an effective tool of earth observation, remote sensing technology makes multi-period and extensive observation in the wetlands possible on regional scale. Classification and biomass estimation of plants in the wetlands by using remote sensing technology could help us to assess wetland resources and evaluate the health status of the wetlands quantitatively. However, many studies have revealed that estimation based on single type of remote sensing data does not perform well in accuracy and can't acquire more fine information about the plants in the wetlands. Compared with estimation by single remote sensing data, information extraction based multi-source remote sensing data has more tremendous application prospects in the observation field of plants in the wetlands. This paper summarized applications of multi-source remote sensing to the classification and biomass estimation of the plants in the wetlands from following several aspects: types of remote sensing data applied to the wetlands; multi-source remote sensing data and their fusion technology; the methods of classification on the plants in the wetlands based on remote sensing technology; the applications on identifying the types of the plants in the wetlands based on multi-source remote sensing data; the models of estimating biomass of the plants in the wetlands using multi-source remote sensing data. The advantages and disadvantages of multi-source remote sensing data and their future development in this field were also discussed.