Abstract: Based on the analysis of chemical composition, isotopes and hydro-geologic features of the hot spring in karst geothermal field, east Liaocheng city, the origin and evolution of the hot spring were studied in the paper. The results show that the formation of the hot spring is controlled by deep faults and basement structure. And it is the consequence of natural comprehensive function during a long geological history. The hot spring is moderate or high degree metamorphic water originated from the infiltrating modern meteoric water, among which forty-year old ancient water dominates, while the new water is less, which can be explained by the relationship between δD and δ18O and tritium (T) values and coefficient of hydro-chemical characteristics. The formation of hydrochemistry ingredient is primarily leaching and dissolving, and the trace element ingredient is rich, which reflect that the groundwater passed through a long and complex runoff process and deep cycle.