Abstract: To assess the conservation effectiveness of nature reserves is of great significance to improve the conservation and management and optimization of nature reserves. In this paper, we assessed the conservation effectiveness of Dongting lake natural reserve network during 1982-2018 by using the landscape dynamic, quality index of protected landscape, interference index of anthropogenic interference landscape, and the composite index of landscape conservation efficiency. The results showed that the proportion of the protected landscape in Dongting lake natural reserve network decreased from 85.20% to 85.13% during 1982-2018, and the area of lakes and rivers decreased quickly, while the area of swamps and beaches increased significantly. The mutual transfer of various landscapes was obvious. Area proportion transformed to and from other types of swamps, beaches, reservoirs, and woodlands particularly high, and the landscape transformation index was 1.80. The area of anthropogenic interference landscape increased significantly during 1982-2010, and the area decreased rapidly after 2010, but the planted forest had a great negative impact on the protection effect. The quality index of protected landscapes of the nature reserve network increased from 52.11 to 52.26, and the interference index of anthropogenic interference landscape was −2.15 and −2.10 in 1982 and 2018. This showed that the quality of the protective landscape is improved and the artificial disturbance intensity was reduced. The composite index of landscape conservation efficiency of Dongting lake natural reserve network was 0.40% during 1982-2018. It showed that the landscape conservation efficiency of Dongting lake natural reserve network was “good”. The research can provide a scientific basis for optimizing the spatial layout of the Nature Reserve in Dongting Lake and improving its protection and management level.