The faulted lacustrine basin in eastern China is rich in underground hot water resources. The lack of isotopic and trace element analysis tests for underground hot water in this type of basin limits the research of the origin and evolution of underground hot water in this area and restricts the exploration and development of underground hot water. In this study，Dongying Sag was taken as the main research area，the constant ion characteristics，ion parameters and other indicators were first used to classify the underground hot water in the research area. The source and evolution process of underground hot water in the faulted lacustrine basin were discussed by using temperature and pressure characteristics of different types of underground hot water and the water-rock reaction products of reservoirs. Studies have shown that there are three different types of underground hot water in Dongying Sag. The first type of underground hot water is meteoric water which is concentrated in Dongying Formation and Guantao Formation，and it is in an open environment of normal temperature and atmospheric pressure that experiences a certain degree of atmospheric infiltration transformation and evaporation concentration of atmospheric precipitation. The second type of underground hot water is the lake water which is concentrated in the three segments of Shahejie Formation，Dongying Formation and Guantao Formation，and it is in an atmospheric-overpressure transition system that experiences water consumption concentration，CO2 injection from organic sources and related waterrock reactions. The third type of underground hot water is the origin saline lacustrine water which is concentrated in the fourth member and the third member of Shahejie Formation，and it is totally in an overpressure system that experiences water consumption concentration，CO2 injection from organic sources and karstenite dissolution.