Abstract: To study the characteristics of urban water quality and its influencing factors, monitor and management of urban landscape water, measured the main chemical ions in the lower reaches of the Youhe River Basin, analyzed the water chemistry and genesis in study area by Gibbs diagram and Piper diagram.The total ion concentration in the study section was wavy from the Youhe Reservoir. More Na+ and Ca2+ mainly from the karst and weathering products of soluble rocks were found. NH4+ and K+ coefficients of variation were larger, suggesting which were affected by human activities. Surface water in the rural sewage discharge area was supplied by groundwater with high conductivity(EC) and high Cl- mass concentration values, the total ion concentration in the area showed high value, suggesting serious water pollution. Positive correlation were found between Na+, SO42-, Cl-, NO2- that soluble sodium in urban sewage was the main source of pollution.Water quality control in the study area should pay more attention to the management and treatment of rural sewage, pay special attention to the problem of sodium and salt pollution caused by sewage.