Abstract: Taking Dongting Lake region as an example, with the support of 3S technology, identified the key areas of green space ecological network and analyzed their features with the methods of comprehensive evaluation of ecosystem service, comprehensive evaluation of biodiversity index and morphological spatial pattern analysis. The results showed that the spatial distribution of the key green space ecological areas in Dongting Lake region was unbalanced. They were mainly distributed in the northwest, southwest, east and middle of the study region. It consisted of forest land, shrub land, orchard land, grass land and water areas. The area of forest land, shrub land and water areas was 8415.18, 3410.31 km² and 1922.27 km² respectively, the sum of the 3 areas accounted for 95.9% of the key areas, and 30.32% of the total area of the study region. The average altitude of forest land and shrub land was 371.6 m and 402.6 m respectively, which were mainly located in the mountainous area and rich in biological resources. The average altitude of the water area was 33.5 m, which was mainly made up Dongting Lake wetlands in the middle of the study region. There were almost no key patches in the surrounded plain region, the ecological risk of this region was high. The results can provide references and scientific instructions for the spatial planning of national land and the building of green space ecological network in Dongting Lake region.