Long-term monitoring of soil properties is important for management and restoration of the Dongting Lake wetland after implementation of the converting farmland to lake (CFTL) project. Soil physical, chemical and biological properties are important components of the soil environment, and they affect water regulation and vegetation succession of wetland ecosystems. Although there have been reports on changes in soil properties, including soil particle size composition, C, N and P contents, microbial biomass C, N, P, and enzyme activities after CFTL, there is still a lack of information evaluating the ecological consequences of the CFTL project on the soil environment. Therefore, the objectives of this study were to explore correlations between soil environmental conditions and the processes of ecosystem restoration and succession, and to investigate the key factors controlling the recovery of the soil environment in degraded ecosystems of the Dongting Lake wetland. Three types of CFTL projects (poplar plantation, reed plantation, and natural restoration, e.g. aquiculture), farmland (dryland and paddy) and natural wetland ecosystems (reed marsh and Carex marsh) were selected, and soil samples were taken at depths of 0-30 cm (topsoil), 30-60 cm (subsoil), and 60-100 cm (deep soil) in November 2006. Soil physical, chemical and biological properties including soil particle size composition (sand, 2.0-0.05 mm; silt, 0.05-0.002 mm; clay, <0.002 mm), soil organic matter (SOM), total nitrogen, total phosphorus, total potassium, and invertase, urease, catalase, and alkaline phosphatase activities were determined. Principal component analysis and cluster analysis were used to interpret the data. Clear relationships between soil environmental conditions and ecosystem restoration were found. The soil environment of the aquiculture ecosystem was very similar to that of the Carex marsh, indicating that natural restoration is the best approach to wetland restoration among the three types of CFTL. The soil environment of the poplar plantation was significantly different from that of the natural marsh. However, the poplar plantation performed better in improving the ecosystem function of SOM accumulation and clay particle formation than did the reed plantation. The soil environment of the paddy was very similar to that of the aquiculture ecosystem and the Carex marsh, but the soil of the dryland was different from that of the natural wetland, suggesting that the hydrological regime is the most important factor affecting restoration of the soil environment, and that human disturbance is of lesser importance. Importance analysis and one-way analysis of variance based on factor scores both showed that accumulation of clay, TP, TK, and SOM in the topsoil were the most important processes separating the group of relatively dry systems (dryland, poplar and reed plantations, and the reed marsh ecosystem) and the group of submersed ecosystems (Carex marsh, aquiculture and paddy ecosystems). This suggests that submersion can improve the capacity of the soil environment to accumulate clay, SOM, P, and K. However, ecosystems with fertilizer input (dryland, and the poplar and reed plantations) possess higher N accumulation and urease enzyme activity, implying that fertilization can help to maintain the supply of N, but on the other hand may increase the risk of N contamination.