In this paper,based on the daily precipitation data of 174 stations in Guangdong Province and Guangxi Zhuang Autonomous Region(hereinafter collectively referred to as the Guangdong-Guangxi region) at a total of 2 400 China surface meteorological stations from 1979 to 2017,monthly sea surface temperature data of the Hadley Center in the UK and monthly NCEP/NCAR reanalysis data,the influence mechanism of the Indian Ocean Dipole(IOD) on the extreme positive anomaly of precipitation in southern China during the late flood season (July-September) of 1994 is analyzed.The study results show that the positive IOD event in 1994 can affect the above-normal precipitation over Guangdong-Guangxi region during post-flood season.In addition,when the sea surface temperature in the tropical southeastern Indian Ocean(eastern pole of IOD) is negative,water vapor is transported to the Guangdong-Guangxi region along the abnormal water vapor transport channels in the northern part of India,northern part of the Bay of Bengal,central part of the Bay of Bengal,central part of the Central South Peninsula,and two parts of the Bay of Bengal,resulting in an abnormal convergence of water vapor in the Guangdong-Guangxi region.At the same time,when the SST anomaly in the eastern pole of IOD is low,the anomalous convergence of the lower troposphere and anomalous divergence of the upper troposphere in the Guangdong-Guangxi region will then be controlled by the anomalous upward motion,which will result in meridional vertical circulation.The above physical mechanisms work together,thereby leading to extreme positive precipitation anomalies in the Guangdong-Guangxi region in the flood season after 1994.