The invention provides a thermal power plant industrial cooling water system and a start and close control method thereof. The system comprises an industrial water pool, a first industrial cooling water pump, a second industrial cooling water pump, a third industrial cooling water pump, a first condensate pump cooler, a second condensate pump cooler, a third condensate pump cooler, a sealing oil vacuum pump cooler, an air compressor cooler, a first water feed pump booster pump cooler, a second water feed pump booster pump cooler, a first start furnace water feed pump cooler, a second start furnace water feed pump cooler, a furnace water circulation pump cooler, a water replenishing electric door, a water replenishing regulating valve, a recirculation regulating valve, a water supply main pipe electric door, a water supply main pipe exhausting electric door and a back water main pipe electric door. According to the thermal power plant industrial cooling water system and the start and close control method thereof, in the condition that the industrial cooling water system is fully closed, the industrial cooling water system is automatically started; in the condition that the industrial cooling water system operates, the industrial cooling water system is automatically closed; and human judgment is taken into account, and leapfrog operation of the programmed logic of the industrial cooling water system is achieved.