Abstract: Taking a large wet cooling tower of a 1 000 MW unit as the research object, a 3D numerical calculation model of the three-zone synergistic efficiency enhancement pattern was established based on partition water distribution, non-equidistant fillings layout and dry-wet hybrid rain zone, and the accuracy of model was validated. Meanwhile, researches were emphatically conducted on the effect of the three-zone synergistic efficiency enhancement pattern on the thermal and resistance performance of the wet cooling tower under variable operating conditions. Results show that the thermal and resistance performance of the three-zone synergistic cooling tower is significantly superior to that of the conventional cooling tower under variable operating conditions. Within the study range of circulating water flow rate, tower inlet water temperature, air dry-bulb temperature and air humidity, after adopting the three-zone synergistic efficiency enhancement pattern, the water temperature drop is increased by 0.63-0.72 K on average, the cooling efficiency is increased by 3.66-4.11 percentage points on average, the Merkel number is increased by 0.16-0.20 on average, and the ventilation rate is increased by 10.54%-10.91% on average.