Jiaodong Peninsula is one of the regions with the most abundant low- medium temperature convective geothermal resources in the eastern coastal areas of China. This paper discussed hydrochemical and recharge characteristic, heat reservior temperature, geothermal circulation depth and renewable capacity using hydrochemistry analysis of geothermal fluids in Jiaodong Peninsula. Geothermal fluid samples from 15 natural hot spring and nearby bedrocks, as well as Quaternary water systems were analyzed using routine water quality and deuterium- oxygen isotope analysis. γNa/γCl and γSO4/γCl ratios of geothermal fluid, along with pipeline model and fault zone model, indicate that geochemical types of geothermal fluids in Jiaodong Peninsula are dominated by Cl- Na or Cl- Na·Ca type and HCO3·SO4- Na, SO4·HCO3- Na type, with salinity of 0. 45～7. 68g/L and pH 7. 3.~8. 63. The geothermal fluid is mainly derived from atmospheric rainfall, and no connection with the shallow groundwater around the geothermal field. The circulation depth ranges from 1. 5 km to 10 km, suggesting that geothermal fluid belongs to deep- circulating geothermal fluid. The geothermal fluids in the study area have not reached the water- rock equilibrium. For geothermal fields with geothermal fluids with high ratios of γNa/γCl and γSO4/γCl, their corresponding geothermal circulation depth is relatively shallow, indicaitng that the geothermal fluid hydrodynamic environment has poor sealing performance and strong renewability and geothermal fluid is in the continuous recharge- runoff- discharge process. Some geothermal fields with ratios of γNa/γCl and γSO4/γCl close to seawater result from the deep and long circulation of geothermal fluids and the decarbonation of geothermal fluids. The analysis of hydrochemistry characteristics of low- medium temperature convective geothermal fluids in the Jiaodong area will help to enhance people’s understanding of the formation mechanism of this type of geothermal resources.