Fire, as an important regulator of the ecosystem, has significant impacts on plant community structure and ecosystem function, but few studies have been conducted in wetland ecosystems. In this paper, we investigated the impacts of fire on soil properties of the dominant community types-Miscanthus sacchariflorus and Carex brevicuspis at Lake Dongting wetlands through field survey and laboratory analyses. The results indicated that soil nitrate nitrogen content of Carex brevicuspis significantly reduced by 64.6% and organic matter content significantly increased by 26.3% after the burning, which were in contrast with that in Miscanthus sacchariflorus communities, whose soil nitrate nitrogen contents ignificantly increased by 186.9% and organic matter content significantly reduced by 22.9% after the burning. After the burning, total nitrogen, ammonia nitrogen, total phosphorus and total carbon content of Carex brevicuspis community significantly increased by 75.4%, 36.6%, 102.7%, 76.9%, respectively, but no significant changes in Miscanthus sacchariflorus community. Generally, unreasonable fire is the most common reason for soil properties changes, the burning has little impacts on soil nutrients of Miscanthus sacchariflorus community at the Lake Dongting wetland, which suggested that fire could be a management tool for reed fields (mainly Miscanthus sacchariflorus communities). Burning can release soil nutrients and stimulate sprouting and growth of Carex brevicuspis community, which may aggregate livestock grazing. This study provides a theoretical guidance for management of lacustrine wetland ecosystems. So, the research of this process and mechanism of unreasonable fire is of great significance to the protection of wetlands and the management of ecosystem.