Abstract:To understand the mechanism of the ecological engineering way for controlling Spatina alterniflora, a typical wetland in the core area of Yancheng Nature Reserve was chosen as a reference to study its natural succession. By employing a space-for-time substitution approach,a succession sequence of time series was built. After analyzing the data of related environmental factors with the method of Principal Component Analysis (PCA), three principal components were obtained. Through multiple linear regression analysis, a succession model of coastal wetland ecosystem was built up using the three principal components we got as parameters to study how environmental factors function in succession process. The model showed that in the nature succession process of coastal wetland vegetation, moisture, salinity, and soil nutrients all had played important roles, so as competition between species and different factors had different impacts on different succession stages. As a reference wetland, this study could help us to evaluate the degradation of wetland and the effect of wetland restoration,as well as to help us to achieve the balance of utilization and reservation.