Wetland ecology monitoring is an important technical guarantee for the protection and restoration of fragile wetland environments. In view of the degradation of the functional vegetation Suaeda heteroptera ( S. heteroptera ) in the Liao River Estuary wetland, an online monitoring method named the Wetland Image Monitoring System (WIMS) was established to obtain real-time, continuous, high spatial and temporal resolution data about the area and height of S. heteroptera . Based on the monitoring data, we confirmed the best model to describe the change process of the area and height for S. heteroptera . The results showed that the growth of S. heteroptera could be divided into three stages: in April and May, the area and height of the S. heteroptera increased rapidly; from June to September, the growth rate slowed down; after October, the area and height of S. heteroptera gradually stabilized. The modeling results showed that the Bertalanffy model had the best simulation performance on the change of the area. While for the height simulation, the segment model composed of the linear and Gompertz models could effectively reduce the simulation error and improve the fit accuracy compared with the single model. In addition, the WIMS has the potential to capture other important ecological factors in small regions, such as benthic animals, birds, waterlogging condition, etc. This observing method can provide high-resolution and abundant data for further exploration of the degradation of typical ecosystems under climate change and human activities.