Abstract: With the acceleration of urbanization in the Yangtze River economic belt, a series of ecological security problems have emerged, which seriously restrict the development of the Yangtze River economic belt. The research on ecological security early warning is helpful to discover the factors threatening ecological security in time, and forecast and warn the future development trend of ecological security, so as to achieve “pre-control”. This article takes the whole basin of “eleven provinces and cities” in the Yangtze River economic belt as the research area, and constructs an ecological security early warning index system based on the PSR model. Then, establishes a simulation model of urban ecological security system by the system dynamics theory, which aiming to reveal the characteristics of ecological security changes in the Yangtze River economic belt from 2007 to 2025 and provide a theoretical basis for ecological security early warning. The research show that: (1) From 2007 to 2025, the overall ecological security level of 11 provinces in the Yangtze River Economic Belt will increase year by year, and the trend will be more significant after 2013. (2) The difference of ecological security between regions is significant, showing the spatial characteristics of “higher in the East and West, lower in the middle”. (3) In terms of indicators, fixed asset investment, urbanization rate and the proportion of environmental protection investment in GDP have the greatest impact on the pressure, state and response of ecological security.