Abstract: Based on the NCEP/ NCAR reanalysis monthly mean data and NOAA global daily precipitation data, the present study analyzes the temporal and spatial characteristics of the vertical structure variation of the South China Sea summer monsoon (SCS-SM) by using the empirical orthogonal function (EOF) method, and then discusses the influence and mechanism of the vertical structure of the SCS-SM on summer precipitation in China. The main conclusions are as follows: (1) The vertical structures of the SCS-SM feature obvious inter-annual and interdecadal variation. The first mode of EOF mainly shows the inter-annual variation of the vertical structure of the SCS-SM, which consists of two typical structural changes, i.e., the simultaneous increase (decrease) of the southwest wind in the lower troposphere and the northeast wind in the upper troposphere (referred to as "lower-upper troposphere simultaneous enhancement" and "lower-higher troposphere simultaneous weakening"); the second mode of EOF mainly features the interdecadal change of the vertical structure of the SCS-SM, which can be divided into two vertical structure changes of two different ages (periods): the change of the southwest wind (northeast wind) at the lower troposphere (upper troposphere) from enhancement to weakening from bottom to top with height, and the change of the southwest wind (northeast wind) at the lower troposphere (upper troposphere) from weakening to enhancement (referred to as "low troposphere from stronger to weaker-upper troposphere from stronger to weaker" and "low troposphere from weaker to stronger-upper troposphere from weaker to stronger"). (2) The changes of the SCS-SM vertical structure significantly affect the anomalous changes of summer precipitation in eastern China by changing the circulation anomalies in the lower and upper troposphere. When the SCS-SM presents a vertical structure of "lower-upper troposphere simultaneous enhancement", the low-latitude tropical monsoon circulation in the SCS is anomalously strengthened, and there are the low-level divergence, upper-level convergence and abnormal subsidence movement in the Yangtze River Basin. At the same time, southern China and northeastern China are characterized by low-level convergence, upper-level divergence, and abnormal ascending movements. Such a low-upper-level circulation configuration leads to abnormally high precipitation in southern China, less precipitation in the Yangtze River Basin, and more precipitation in the north. It is the opposite in the "lower-higher troposphere simultaneous weakening" years. When the SCS-SM vertical structure is in the period of "low troposphere from weaker to stronger-upper troposphere from weaker to stronger", from southern China to northeastern China, the circulation conditions of low-level convergence (divergence) and high-level convergence (convergence) are favorable to the rising (sinking) movement, which leads to the increase of precipitation in southern China and Jianghuai areas, and the decrease in the precipitation in Jiangnan and northeastern China. The opposite is true for the period of "low troposphere from stronger to weaker-upper troposphere from stronger to weaker".