Abstract: To further understand the occurrence, development and movement of East Asian monsoon depressions (EAMD) and the causes of extreme precipitation events in South China, the activities of an EAMD that caused the heavy rainstorm in Beihai, Guangxi on 8 June 2023 are analyzed using the ERA5 reanalysis data and the tracking software TempestExtremes. From the moving track of the EAMD, it can be seen that from 7 to 9 June, the EAMD mainly moved near Beihai, and the large amount of water vapor brought by it had an important impact on the formation of the heavy rainstorm. The structural differences between different development stages of the EAMD show that from the initial stage to the mature stage, the EAMD had an asymmetrical vertical structure, with the tilt direction changing from southeast-northwest to northeast-southwest as the height increased. The weakening of the EAMD after reaching its peak intensity may be related to the "filling" effect of cold air entering the EAMD from the north. When the EAMD was about to dissipate, the areas of large deviation from zonal mean in the upper atmosphere had obviously deviated from the center of the EAMD, and there were more descending motions in the deviation from zonal mean of vertical circulation. It is worth noting that an obvious “cold core” always existed in the middle and lower atmosphere of the EAMD, which was one of the possible factors preventing further development of the EAMD. The results also show that the peripheral flow of the Western Pacific Subtropical high played a leading role in the moving path of the EAMD, but the indirect influence of Typhoon “Guchol” cannot be ignored. In addition, after the EAMD landed, the northerly cold air hindered the movement of the EAMD to a certain extent.