Due to the impact of Taiwan geography and topography, flow rate in rivers goes up and down intensely with rainfall. Rivers are usually lack of dilution capacity, especially during dry season with little rainfall. Water quality has been damaged by untreated municipal wastewater, industrial wastewater and landfill leachate discharged into rivers through gutters, hidden pipes or tributaries discharger, especially obvious in metropolitan rivers. Love river is a typical metropolitan river. It has been under restoration by stages since 1977. Due to the lack of restoration in its upstream segments, this project is to analyze current water quality and to estimate pollutant loading through integration of related materials and documents in Love rivers, as well as to simulate water quality by WASP model through the analyses of measurement data for main and tributaries dischargers as the evaluation of pollution improvement action. Past water quality analyses shows that most upstream segments (upstream of sluicegate under water in Baozhu gutter) are between medium and serious polluted. In addition, results of water quality and flow rates in tributaries discharger shows that (River Pollution Index, RPI) in southern discharger left to Yucheng bridge, K trunk discharger and Baozhu gutter discharger are between 7.25 to 8.25, indicating that this tributaries discharger is the primary source for Lover river pollution. The objectives of this research are to lower the level of upstream pollution through the policies provided through related restoration experience before the sewage system for Kaohisung city is completely developed. As shown by the simulation of pollution reduction, through the combination of water interception and water injection, biochemical oxygen demand and ammonia nitrogen in water segments downstream of Dingxin bridge was reduced above 65% and 50%, respectively. The fact that water is discharged into Love river after purification by the combination of water interception and source water treated by water purification engineering is beneficial for the reduction of downstream biochemical oxygen demand and ammonia, as well as the improvement of dissolved oxygen to eventually meet the goal of lowering levels of water pollution. The Forecast results of the water quality model used in this study can evaluate the cost-efficiency of pollution reduction action and to provide priority restoration policy in the future as references in the following studies.