Based on actual land use in Yancheng city, this paper establishes the ecological security of the land index system from perspectives of economy, society and ecological environment. Using the catastrophe theory and pressure-state-response (PSR) model, the purpose of the research was to judge the degree of land ecological security in Yancheng city from 2002 to 2011 and determine the requirements to ensure the sustainable development of this region. The results showed that over the ten years, the values of pressure, state, response and synthetic values of the land ecological security was evaluated as safe in the year of 2003 and 2007, at middle level in the year of 2002 and from 2004 to 2006, then drops to insecure for years 2008 to 2009 and very insecure from 2011 to 2012.The ecological security level and circumstance of land use in Yancheng city has generally declined. During this period, the land use pattern of Yancheng was under tremendous pressure from the conflict between rapid urbanization and economic development, and conservation and rehabilitation of the eco-environment. This research shows that conditions for the land ecosystems of Yancheng city are not optimistic and as such, should draw the attention of responsible government departments. Future policy options should aim to mitigate these problems through control of population growth and improvement to quality of life, protection of wetland and forest land, application of scientific concepts of development, coordination of economic development and land utility, and strengthening the control functions of land-use planning.