In June 2024, precipitation in eastern China exhibited a distinct spatial distribution, characterized by "droughts in northern China and floods in southern China". Notably, precipitation in the south of the Yangtze River exceeded the historic record since 1961. Both the results of the statistical analysis and the case study demonstrate that the anomalous southerly water transportation on the western side of the western Pacific subtropical high (WPSH) was a significant contributing factor. However, in June 2024, the general circulation in the west of 110°E exhibited distinctive characteristics compared to historical events. The eastern boundary of the North Africa high (NAH) exhibited a notable eastward and southward extension, establishing a connection with the western boundary of the WPSH over the southern tropical Indian Ocean. This resulted in the formation of an "inverted Ω" circulation pattern, a phenomenon that has never been observed previously. Besides the El Ni?o, the record-breaking warm sea surface temperature (SST) in the western tropical Indian Ocean was another significant influencing factor to the floods in the south of the Yangtze River in early summer. During the months of January and February 2024, the SSTa over (20°S-20°N, 40°-75°E), the west part of tropical Indian ocean, exceeded 1 °C for the first time. The thermal effect of the underlying surface resulted in an increase in air temperature below 600 hPa over the domain. The thermal expansion of the air column led to an increase in potential height over the eastern boundary of the NAH, which in turn led to an intensification of the north wind component. It can be concluded that the formation of the "inverted Ω" circulation pattern was a result of the eastward extension of the NAH and westward extension of the WPSH, respectively, which led to the development of a strong cyclonic anomaly circulation over the equatorial Indian Ocean. The anomalous southerly wind on its eastern side converged and enhanced the southwest moisture flow from the Bay of Bengal to the south of the Yangtze River, resulting in abnormal rainfall in the latter. Statistical analysis from historical observations also verified the conclusion.