Abstract: The Yangtze River basin experienced a record-breaking extreme high-temperature event during July and August 2022. Spectral analysis of ERA5 reanalysis data and CN05.1 grid point data revealed a low-frequency component with a duration of 30–64 days associated with this heatwave. Linear regression analysis indicated that the Eurasian subtropical teleconnection and two key tropical convection activities in the region were closely linked to the event. Further analysis using a linear baroclinic model revealed that anomalous convection over the Arabian Sea–Pakistan area and the South China Sea played critical roles in modulating atmospheric circulation over the Yangtze River basin at different stages of the heatwave through teleconnection patterns. Specifically, during both positive and negative phases of the low-frequency cycle, enhanced convective activities near the Arabian Sea–Pakistan region modulated the upper tropospheric subtropical Rossby wave train in the north, thereby affecting downstream circulation anomalies over the Yangtze River basin. Conversely, convective anomalies over the South China Sea initiated Rossby waves that influenced the basin via the Pacific–Japan teleconnection pattern. During the negative phase of the low-frequency temperature cycle, weakened convection over the South China Sea prevailed, resulting in anomalous cyclonic circulation with meridional cold advection in the Yangtze River basin, leading to cooling in the region. In contrast to the response to the convection in the Arabian Sea, the Yangtze River basin is situated within a cyclonic circulation characterized by abnormal positive vorticity, and zonal cold advection contributes to cooling in the region. During the positive phase of the low-frequency temperature cycle, the response to the strengthened convection in the South China Sea and the strengthened convection in the Arabian Sea is a synchronous phase, and the Yangtze River basin is located in an anticyclonic circulation with an anomalous negative vorticity. At this time, the Yangtze River basin is located on the southerly side within the anticyclonic circulation, and the sinking adiabatic motion and meridional warm advection strengthen the positive temperature anomaly during this period. This study elucidates the impact mechanisms of an extreme high-temperature event in the Yangtze River basin and provides insights for forecasting future summer extreme temperature events.