Source research of the hot spring is very important to do the geothermal resources evaluating, and has a guidance for sustainable exploitation and utilization with geothermal resources. Beiwenquan hot springs in Chongqing is selected to be study area, and hydrochemical method, D, O isotope and on-line monitoring system are used to do this study. It is found that, Beiwenquan hot spring in Chongqing is the medium-low temperature, shallow, neutral geothermal water, and the hydrochemical style is SO4-Ca. The value of the δ 18O of Beiwenquan is -8.48‰～-7.09‰, and δD is -55.46‰～-53.26‰. The recharge of this geothermal water is rain water and the recharge area is the karst outcropping area of 641~1 206 m altitude. Marshall and CDTP300 slot-line monitoring system are used to do high resolution real-time online monitoring for the North hot springs and found some results. 1) The hydrogeochemical features have little change over the long term, which means the hydrochemical features and the water-rock interaction in thermal aquifer is stable. 2) However, the discharge and rainfall in the study area is a lag relationship, the discharge of hot spring is almost 6 month delete response on rainfall, the discharge of the hot spring is lower in rainy season, while higher during the dry season. Hydrological features of the hot spring have a certain changes after a rain. About 20 days after rainfall, temperature and electric conductivity will be some decline and the discharge will increase. The origin of these geothermal water is precipitation and its recharge is not only the long-term and long-time geothermal aquifer but also the water supply from the shallow underground water and rain water in the process of thermal water rising.