Abstract: Composite extreme low temperature events have a significant impact on the economy, society, and people"s lives in southern China. This study utilizes daily minimum temperature, relative humidity data from China’s CN05.1 dataset (1982~2022), along with ERA5 reanalysis data, to explore the temporal and spatial distribution characteristics and potential causes of two types of composite extreme low temperature events in southern China during the winter season. The results show that Cold-Dry events are distributed across most of southern China, with high-frequency centers in the eastern and Jianghuai regions, while Cold-Wet events exhibit a south-to-north decreasing trend, mainly occurring in the southwestern and western South China regions. Furthermore, over the past 41 years, Cold-Dry events have shown an increasing trend in most southern regions of China, whereas Cold-Wet events have significantly decreased, with notable interannual variability in both event types. Cold-dry events typically occur in early winter, while Cold-Wet events are more likely to happen in late winter. Further analysis of the different causes of these two types of events reveals that the early and late winter periods are associated with distinct atmospheric circulation systems and moisture conditions. The mid-to-high-latitude ridge over Asia and the East Asian trough are key circulation features for Cold-Dry events, providing favorable conditions for the southward intrusion of cold air. During this period, there is significant moisture divergence in southern China, which promotes the occurrence of Cold-Dry events. On the other hand, during the occurrence of Cold-Wet events, the northern branch of the wave pattern maintains a two-trough, one-ridge circulation over the middle and high latitudes of the Eastern Hemisphere. The southern branch of the wave pattern, propagating through West Asia and the Middle East, deepens the southern trough and interacts with the anomalous anticyclone over the western Pacific, transporting warm and moist air to southern China, leading to moisture convergence in the region and providing abundant moisture for Cold-Wet events.