Abstract: Study on water vapor transport is beneficial for better understanding the process of extreme precipitation. However, the precipitation system is complex and precipitation isotopes exhibit randomness, which makes it large uncertainty to use precipitation isotopes to trace water vapor transport. Information entropy has been employed to study the probability distribution characteristics of precipitation isotopic compositions in China, and it shows a strong linear relationship between hydrogen and oxygen precipitation isotopic information entropies, with a slope that is close to one. The spatial and temporal distributions of precipitation isotope information entropy were compared with the mean value of precipitation isotopes. Results showed that the spatial distribution of precipitation isotopic information entropy can suitably reveal the movement of water vapor from the ocean to continents, but this feature is not reflected by the spatial distribution of the mean value of precipitation isotopes. Precipitation isotope information entropy was applied to trace the three moisture corridors driven by monsoon system in China. Results showed that the spatial distribution of precipitation isotope information entropy can accurately reflect the vapor source and movement of the three moisture corridors and their seasonal changes.