The invention provides a thermal power plant generator stator cooling water system and a start-stop control method thereof. The system comprises a stator cooling water tank, a first stator cooling water pump, a second stator cooling water pump, a first cooler, a second cooler, a stator cooling water temperature control valve, a stator cooling water flow adjustment valve, a stator cooling water supply screen, a water supply screen bypass electric door, an ion exchanger, an ion exchange water replenishing electric door, an ion exchange water replenishing screen, a water replenishing screen bypass electric door, a stator cooling water tank water replenishing electric door, a stator cooling water tank water replenishing adjustment valve, a stator cooling water tank water replenishing bypass electric door and an anti-siphon electric door. In a total stator cooling water system stop state, automatic start of the stator cooling water system can be realized; in a stator cooling water system operation state, automatic stop of the stator cooling water system is realized; and human judgment is considered, jump operation of the system program control logic can be realized.