To understand the interactions among soil nutrients, enzyme activities and aquatic plant diversity in a wetland landscape under human disturbances, a three-year study was carried out in the Napahai wetland, a typical degraded plateau wetland in the northwestern Yunnan, China. The plant community composition changed and the community coverage increased over the wetland succession from primary swamp, through swampy meadow, to meadow. The number of associated species increased, while the dominant species abundances decreased. Through succession, the content of soil organic matter and total nitrogen declined. In contrast, the soil enzyme activity of catalase, protease and invertase increased; however urase declined. The Simpson and Shannon-Weiner indices of aquatic plant diversity were both significantly positively correlated with catalase, protease and invertase, and negatively correlated with urase, soil organic matter and total nitrogen. Similarly, soil organic matter and total nitrogen were negatively correlated with catalase, protease and invertase but positively correlated with urase. This wetland succession is thus related to the type and intensity of human disturbances, the characteristics of plant diversity, soil fertility and soil enzyme activity. The results from this study will facilitate understanding of the ecological processes and mechanisms contributing to degraded wetlands subject to anthropogenic pressure, and provide guidelines for the assessment of wetland health, sound environmental management and restoration.