This study investigates the general circulation and external forcing factors which synergistically impact interannual variation of regional persistent high-temperature events in South China (RPH) during summer. Several observational datasets for nearly 60 years from meteorological stations and the NCEP/NCAR Global Reanalysis Data are used. The RPH index is defined based on historical processes of regional persistent high temperature in South China. Under the control of anti-cyclone throughout the troposphere, deep atmospheric dynamics and thermal anomalies occupy vertically over South China during the years with high RPHs. The interannual variation of RPH of South China is also closely relative to eastward-propagating wave trains over Eurasia and large circulation anomaly in the tropics due to the joint influence of sea surface temperature anomaly (SSTA) from tropical Indian Ocean, tropical Pacific and North Atlantic. The generation of anti-cyclone anomaly over South China Sea-western Pacific, which leads to the westward extension of strengthened western Pacific subtropical high, is resulted from the SSTA of tropical Indian Ocean and tropical Pacific. Meanwhile, the enhancement of wave trains over Eurasia in the upper troposphere, which leads to the eastward extension of strengthened South Asia high, is resulted from the SSTA of North Atlantic. Thus, strong descending is generated under the control of anti-cyclone throughout the troposphere over South China with combined effect of these key regions of oceans. And the high RPH is resulted from this strong descending which brings both adiabatic heating and strengthened solar radiation heating at the surface.