Cities over China are selected for urban wateresources measurement, assessment and system analysis. Water balance elements of urban hydrological cycle have been measured and investigated, then checked by means of water balance equation in urban areas.Based on investigation and analysis,characteristions of urban water utilization system have been deeply understood and water usage quotas have been presented in details. Simulation models and optimal management model have been established and checked by means of system analysis method and large scale system optimization technique. It is shown that the results of the case study is satisfactory.