Abstract: The El Nio-Southern Oscillation event (ENSO) causes anomalous global climate and also causes abnormal changes in the global barometric pressure. The traditional atmospheric pressure detection technology has the problems of high cost, lack of data in the marine area and uneven distribution. In order to solve the above problems, this paper proposes to study the changes of atmospheric pressure during the ENSO by using the global atmospheric pressure retrieved from the GNSS occultation data. In this paper, GNSS occultation data from 2006 to 2008 are used to calculate the change of atmospheric pressure at 2 km by geometric optical inversion. The global atmospheric pressure difference among El Nio (december 2006), La Nia (december 2007) and the normal year (december 2008) is taken as the difference and the change of atmospheric pressure is analyzed. The experimental results show that using the GNSS occultation data to draw a map of atmospheric pressure changes at a certain height on the global scale, the atmospheric pressure changes during the ENSO can be visually demonstrated, providing a convenient reference for relevant climate change research.