The utility model provides a generator stator cooling water system of thermal power plant, this system includes: stator coolant tank, first stator cooling water pump, second stator cooling water pump, a first cooler, a second cooler, stator cooling water temperature -sensing valve, stator cooling water flow governing valve, the stator cooling water supplies water screen, supply water screen bypass electrically operated gate, ion exchanger, ion exchanger moisturizing electrically operated gate, ion exchanger mends water screen, mend water screen bypass electrically operated gate, decide cold water storage cistern moisturizing electrically operated gate, decide the cold water storage cistern moisturizing and transfer the valve, decide cold water storage cistern moisturizing bypass electrically operated gate and prevent the siphon electrically operated gate. The utility model discloses can guarantee that cooling water uninterruptedly flows through inside the stator coil to take away stator coil because of the heat that the loss arouses, assurance stator coil's temperature rise accords with generator operation's requirement. And simultaneously, the utility model discloses still realized making its operation index accord with the designing requirement to the control of electrically conductive degree isoparametric of the pressure of the water that gets into stator coil, temperature, flow, water.