Abstract <p>Droughts in the Yangtze River Basin (YRB) are becoming increasingly frequent, and meteorological drought (MD) is regarded as a precursor of hydrological drought (HD). Studying how MD transforms into HD and exploring the role of the Three Gorges Dam (TGD) in the transformation process are of great significance for drought early warning and disaster prevention and mitigation in the YRB. Based on the runoff data from 1961 to 2020, the SPEI and SRI indices at different time scales, and the SRI index simulated by the SWAT model, this study quantified the impact of the TGD on HD and its influence on drought propagation. The research results show that: (1) The regulation of drought conditions by the TGD has intensified the occurrence of continuous droughts in the upper and lower reaches of the YRB, prolonged the duration of drought conditions, but reduced the intensity and severity of drought conditions. (2) The regulation of the TGD has enabled the YRB to avoid more severe HD during the dry season, and during the wet season, the water storage through the TGD has weakened the flood peak. (3) The operation of the TGD has effectively accelerated the transformation process from MD to hydrological drought in the YRB, significantly reducing the average drought propagation time of the entire basin from 5.3 months to 4.86 months. Specifically, the duration of drought transmission in both the middle and lower reaches has been shortened by 1 month.</p>