The interaction between surface water and groundwater is not only an important part of the water cycle, but also the foundati on of the water assessment and management. The hydraulic connection between surface water and groundwater is strong because of the local climate, geology and topography. The water samples collected from rivers, wells and the Xingkaihu Lake were measured for hydrogen and oxygen isotopes and major cations and anions. The δD values of the three rivers were depleted along the river flow. The stable isotopes of Heilongjiang River were depleted. The lake water stable isotopes were enriched by the evaporation. The stable isotopes of deep wells were depleted than the shallow wells. The precipitation isotopes data of the Sanjiang station of Chinese Network of Isotopes in Precipitation (CHNIP) was used. The local meteoric water line was δD=7.4δ18O-3.1. The water type of rivers and wells was Ca·Mg-HCO3. Human activities effected the water quality and changed the water type in the village. The δ18O was used to divide the runoff percent. The runoff percent of the Songhuajing River and Heilongjiang River was 1:4. The hydrogen and oxygen isotopes and hydrochemical data indicated that the water hydraulic connection among rivers, shallow wells, deep wells and lake was strong. The water management should combine the surface water and groundwater as a single water resource.