It is clear that urban river eco-security model may provide an alternative choice of urban river Engineering Construction decision and correspond to the direction of sustainable city. Our goal is to provide a framework to conceptualize the impacts of various urban river eco-security development strategies over a time scale of several decades, while taking into account interactions and feedback loops between various criteria to the fullest extent allowed by available data and theory. Flooding is serious natural disaster, but there is a lack of integrated strategy on urban river ecosystem management in Taiwan. This study aims to construct a integrated index formwork by function and goal of eco-security of urban river. The other purposes of this research are apply the System Dynamics to understand the trend on forecast modeling. Formulate a system dynamics model to simulate the trend of Tamsui River Eco-Security. This research , construction of five subsystems, “discharge security” ,” purification security”, “water security”, “habitat security” and “biosecurity”. The error value between simulation and real situation are few to prove the model is effective .The study results indicate that the eco-security for Danshui River is going to biomass raising, drainage raising, habitat increasing and pollution reducing. The cogitation has integrated by system dynamic model which coming together to form precaution, water use, conservation and ecological restoration to keep the sustainability of urban nature resources by the research.