As an important part of the Middle-Lower Yangtze Plain, the Poyang Lake Plain is an important commodity grain production base in China, with a good environmental quality, a low level of heavy metal pollution in soil, and a low ratio of pollution sites. Therefore, environmental protection system engineering in Poyang Lake agrees with the environmental protection concept of giving priority to protection, and could be a typical and representative case for the agricultural producing areas in Southern China. This paper clarifies the main environmental problems of the Poyang Lake Plain and analyzes the causes. It proposes environmental quality improvement measures and key projects based on a landscape-forest-lake systemic protection concept, which has important guiding significance for the improvement of environmental quality of the main agricultural producing areas in the Poyang Lake area. The results show that environmental pollution in the Poyang Lake Plain is dominated by heavy metal pollution in soil, the proportion of living-source pollution is increased, livestock and poultry breeding pollution has not yet been effectively curbed, and industrial and mining enterprises as well as the background value of heavy metals in soil are the main causes of pollution. Accordingly, measures should be implemented in the following three aspects. First, multiple environmental factors should be combined to strengthen systematic protection and unified supervision. Second, meticulous management should be performed by focusing on the water environment quality. Third, we should attach importance to environmental emergency plans and strictly control the pollution sources that may enter into the soil.