Water resources have the dual attributes of quantity and quality，which requires the study of initial water rights allocation from the two－dimensional perspective of water quantity and water quality． This paper takes Hefei City as an example，establishes an evaluation index system，and builds an urban two－dimensional initial water rights optimal allocation model． The analysis results show that while we consider the influence between water volume and pollutant discharge and optimizing the configuration，the amount of water allocated in the urban area has been reduced by 122．3 million m3 ． After optimizing distribution，the amount of pollutant discharged of Chaohu City has been reduced by about 20% compared with that before optimization． Other districts and counties have slightly different amounts of increase or decrease in the amount of water or discharged sewage． The amount of water and pollutants allocated after optimal allocation can better reflect the economic and water resources development conditions in the study area． Based on water rights and emission rights，it is feasible to optimize the two－dimensional initial water rights of the city and the result can provide a scientific basis for improving the utilization efficiency of water resources and formulating the scientific discharge of sewage．