The Eltahir calculation model is improved by considering the derivatives of water vapor to adapt to the under-monthly scale assessment of precipitation recycling ratio. By using the ten-day precipitation and evaporation data and NCEP/NCAR daily pressure level reanalysis data, the precipitation recycling ratio over the middlelower reaches of the Changjiang River during Meiyu season in 1998 is estimated. It is found out that about 30 % of precipitation in the research area is contributed by local evaporation during continual heavy rainfall summer in 1998. The greatest contribution is over the southern Anhui and eastern Hubei provinces. The ten-day precipitation recycling ratio varies frequently, The highest value is 67, 8%, while the lowest is just 0,8%. That indicates the high sensibility of land surface hydrology and the instability of land-atmosphere interaction.