Abstract: Abstract：Taihu Basin is one of the fastest growing economies and the most densely regions in China. Affected by changes in land-use/coverage and precipitation conditions, the relationship between water supply and demand in Taihu Basin has been changed. In this paper, we set the following scenarios to evaluate the water supply quantity and demand quantitatively, and analyze the spatio-temporal changes of the supply and demand deficit and surplus areas: one is that we kept the precipitation unchanging and only the land-use changed in Taihu Basin from 1995 to 2015;the other is that we set different precipitation conditions with other parameter unaltered in 2015. The results indicate that: first, the proportion of water demand in the supply increased from 73% to 90% and the proportion of county area relying on foreign water increased from 19% to 33% with the rapid change of land use and coverage during 1995-2015, especially the expansion of construction land up to 106% in the past 20 years. Second, in 2015, the change of supply and demand relationship was more obvious under different precipitation conditions. The lower the precipitation, the more counties with supply and demand deficit. Third, in the drought years, the proportion of water demand in the supply was up to 117% in the whole basin . It showed that, the water supply failed to meet the demand in the drought years. In both cases, the relationship between water supply and demand in the northeast of the taihu basin is more tense than that in the southwest. As the major factors influencing the relationship between water supply and demand in Taihu basin, the changes of land-use affect demand and the changes in precipitation conditions impact supply.