-The GFDL version of the level Illb data set from FGGE is utilized in this paper. The characters of the seasonal evolution and structure of summer monsoon over Eastern Asia are analysed in detail. The results show that the negative temperature departure from the zonal mean value in the lower stratosphere and positive one in the upper troposphere are always observed as a pair in the vertical direction and take shape in a three-level vertical structure of temperature departure together with the negative one in the lower troposphere in the region of summer monsoon. These departures are closely related to the positive departure of specific humidity in the lower and middle troposphere at corresponding regions during the periods of summer monsoon over South China, the Changjiang River region and North China respectively. The positive geopotential height departure is in accordance with the corresponding observations of the South Asian high at that region and is just located between the positive temperature dep The The GFDL version of the level Illb data set from FGGE is taken in this paper. The characters of the seasonal evolution and structure of summer monsoon over Eastern Asia are analyzed in detail. The results show that the negative temperature departure from the zonal mean value in the lower stratosphere and positive one in the upper troposphere are always observed as a pair in the vertical direction and take shape in a three-level vertical structure of temperature departure together with the negative one in the lower troposphere in the region of summer monsoon. These departures are closely related to the positive departure of specific humidity in the lower and middle troposphere at corresponding regions during the periods of summer monsoon over South China, the Changjiang River region and North China respectively. The positive geopotential height departure is in accordance with the corresponding observations of the South Asian high at that region and is just located between the positi ve temperature dep