As China has been vigorously promoting the new-type urbanization and implementing spatial planning policies, city clusters have become the urbanization frontier. But the contradiction between economic development and ecological protection restricts the sustainable urbanization. As the basis of urban development, the changes of land quantity and distribution have a significant impact on the structure and functioning of ecosystem. Therefore, land ecological security assessment of city clusters and predicting future land use patterns of city clusters based on such an assessment are crucial to the sustainability of city clusters. The assessment of land ecological security is the basis of the optimal allocation of land resources, and land use simulation is an important method to predict the trend of land use changes. Combination of the two methods can provide reference for optimizing land use patterns and protecting the eco-environment. By studying the city clusters around Poyang Lake, this paper analyzed land ecological security patterns and changes of the city clusters. Based on the results of land ecological security assessment, the paper set up the business-as-usual scenario and the ecological protection scenario. By combining the multinomial logistic regression and Multi-Criteria Evaluation method (MCE), the paper constructed the CA-Markov model to predict land use patterns in 2030 under the two scenarios, and conducted comparative analyses. Results show: (1) In 2005, 2010, and 2015, the average ecological security of the city clusters around Poyang Lake were 0.574, 0.573, and 0.571, respectively. The security level were low in the middle and high in the east and west in the spatial layout. (2) In 2030, the newly developed urban lands under the business-as-usual scenario will mainly occur in Jiujiang, Shangrao, and Nanchang. Under the ecological protection scenario, the lands for constructing towns and other construction purposes will be restricted properly for compact urban growth. (3)Under the ecological protection scenario, the area of high ecological security zones will be 39.39% larger than that under the business-as-usual scenario,and it tends to be distributed more evenly. The ecological security of the city clusters, including areas around Poyang Lake, the central part of Jiujiang, Xinyu and Ji'an, will be effectively protected. It is hoped that the present study can serve as a reference for the land use planning and ecological protection of thecity clusters around Poyang Lake.