An ecological restoration project was conducted in the upstream portion of the Dagu River to improve the urban river water quality as well as to achieve pollution control and remediation of a sewage drainage river. Plant species for phytoremediation were screened and different species were used in the field project. The growth occurred in the following order: macrophytes > slope plants > submerged plants; among different microphytes, Sagittaria sagittifolia > Phragmites australis > Scirpus tabernaemontani > Typha angustata > Iris pseudacorus; among floating plants, Water lily > Lotus. The pollution status of the water body in the phytoremediation area was monitored and compared with that of a clean water area in Mati Lake at Nankai University and the Outer Ring River of Tianjin. In addition, the effects of remediation on the water quality and ecological toxicity of the drainage water were analyzed and assessed comprehensively to show the effects of the ecological remediation project. The results showed that the water quality was improved by the cultivation of aquatic plants such as Scirpus tabernaemontani. N and P were found to be the main pollutants in the Dagu Drainage River, and heavy metal contamination was not serious. Phytoremediation affected conductivity, total dissolved solids (TDS), salinity and chloride content to some extent. Good remediation results were observed for organic pollutants such as COD, with a degradation rate of 54% around the plants. Water samples in the plant growth area showed much lower COD values than those from areas with no plant growth. The N and P values were also highly relative to clean water, which was assumed to be a result of the bottom sludge with low dissolved oxygen (DO) and pH conditions. Principal component analysis showed that the water quality parameters were mainly nutrient related substances such as ammonia, total nitrogen, total phosphorus, and other items such as pH, DO, conductivity, TDS, salinity and chloride. Comprehensive assessment showed that water quality in the reed root zone was the best. The 17 water quality parameters were grouped into five categories based on cluster analysis, which showed good consistency with the results of principal component analysis. The plate counting method result showed that the microbial numbers surrounding the rhizosphere were high and had higher species diversity. The number of bacteria was lower than that of fungi. Phytoremediation reduced the toxicity of water samples on root elongation of wheat. The water sample was toxic to luminescent bacteria, which indicated potential acute toxicity, but the difference was not significant. The water in the remediation area did not show acute toxicity against daphnia. Further screening of remediation plants should be conducted to identify plants species with higher nitrogen and phosphorus absorption ability to enable the removal of pollutants from contaminated river systems. Additionally, microbial consortium can be added to the water system to increase the decomposition of organic pollutants and transformation of toxic substances, which can improve the efficiency of remediation projects and realize ecological restoration of rivers.