Abstract: Abstract: The change of land cover has a profound influence on the quality and distribution pattern of the regional habitat, thus changing the function and evolution of biodiversity. As a special ecology function zone, the ecological security of Three Gorges Reservoir Area affects the whole Yangtze River valley. The proportion of the total area of Three Gorges Reservoir Area in Chongqing City reaches 80%, and thus the study on land cover change and ecosystem and biodiversity function evolution is beneficial to the regional ecological environment protection, remediation and improvement. Taking Three Gorges Reservoir Area (Chongqing section) as an example, this paper analyzed the evolution and trend of regional land cover and biodiversity function from the year of 2005 to 2020 through the comprehensive use of the CA-Markov (cellular automaton and Markov) model and InVEST (integrated valuation of ecosystem services and tradeoffs) model. For the data used in this paper, one part was from the remote sensing monitoring data in The ecological ten years, which was issued by the Ministry of National Environmental Protection, and the other part was from the land use map in 2015. Based on the software of ArcGIS 10.1, ENVI 5.0 and IDRISI, the land use type was classified into 6 kinds in the evolution and trend of land cover and biodiversity function of the study area. On the basis of the simulation of land cover in 2020 by using CA-Markov model, the InVEST model was used to quantitatively calculate the biodiversity function in 2005, 2010, 2015 and 2020. The results showed that: 1) In the 2 periods of 2005-2010 and 2010-2015, various types of land cover areas and land cover dynamic degrees showed the state of "four increase and two decrease" and "three increase and three decrease". 2) The Kappa coefficient reached 0.92 when the CA-Markov model was used in simulation, which showed that the model could be well applied to the simulation of land cover in Three Gorges Reservoir Area (Chongqing section). 3) The highest values of habitat degradation index in the 4 yeas were 0.168 1, 0.207 1, 0.190 9, and 0.181 2, respectively, and the higher habitat degradation index was located in the city's surrounding areas as well as the banks of the Yangtze River, Jialing River and Wujiang River, and Daba Mountain's habitat degradation index was lower. 4) The good regional habitat quality was mainly distributed in the areas including Daba Mountain, Wuling Mountain and Simian Mountain, while the poor biodiversity function appeared alongside the Yangtze River and Jialing River. The total score and the average score of the 4 years were 34 337 710, 36 829 020, 36 345 590, 35 530 500 and 0.513 9, 0.551 2, 0.543 9, 0.531 7, respectively. 5) The analysis of habitat quality showed that the function of biodiversity was increasing in the past 15 years, which changed from the large scale fluctuation into small area change, and the biodiversity function of the whole region tended to be stable. The research may reveal the influence of dynamic land cover change on biodiversity function, show the important role of the delineation of red line of ecological protection to regional ecological security, and provide scientific basis for optimizing the regional ecological environment, as well as scientific support for the sustainable development of regional economy.