Following the economy growth and commercial and industrial development, the rivers in Taiwan have suffered the environmental degradation due to the overwhelming pollution from domestic and industrial sewage. Recent environmental awareness from the citizen has turned the once ignored issues of pollution mitigation and ecological restoration into the public attention. Traditionally, resort to engineering efforts is always the first priority in dealing with river pollution problem. Nevertheless, treated as the integrated system, the nature of the problem should involve many aspects including social, economic, ecological, environmental, and engineering factors. Meanwhile, the special feature of time-dependent state has also made such system a dynamic and complex problem. It is therefore the current research employs the approach from integrated assessment trying to aggregate related studies and tackling the problem as a complete system. System dynamic, which is capable of dealing with dynamic and complex problems, has been utilized as the simulation tool in this research. The result from computer simulation can be promptly generated, and various scenario analyses can be easily achieved by modifying the model parameters to support better decision-making. Love River wandering through the Kaohsiung metropolitan area is the research target. The system dynamic software STELLA has been used to construct the simulation model, which incorporates water quality model, population growth in the upstream of the watershed, land use variation due to the assumed regional development, diverse rainfall types, ecological assessment of the domestic fishes in the river, and cost-benefit of various pollution control strategies. The system dynamic models are thus able to evaluate the overall impact on the aquatic environment between various management scenarios. Two types of system dynamic models are constructed and verified accordingly to evaluate the impact of the designate gate operations and the sewage treatment strategies on aquatic environment. The simulation based on the gate operation model shows that keeping upper stream gates shut during the initial time span of a rainfall event would have the better effect to prolong the concentration of dissolved oxygen (DO) downs to the lethal concentration (LC50) for the local fish species. In the sewage treatment strategies model, the treatment cost and effect is the primary concern. The results identify the better extending strategy on the treatment plant, which is to use fortified primary treatment by adding disinfectant facilities. The other scenario of building constructed wetland system on the public park can improve water quality with good cost/effect ratio given the land acquisition is not an issue. Keyword¡GIntegrated Assessment, System Dynamic, Sustainable River Aquatic Environment