The distribution and formation of water-stable aggregates in red soils under different land use were studied. The results showed that the contents of >0.25 mm water-stable aggregates increased in the following order: orchard > tea garden > uncropped > upland > woodland. Either the waterstability of aggregates or the content of water-stable aggregates was highly correlated with the contents of soil organic matter. Increased decomposition and decreased input of organic matter after reclamation were responssible for the decrease in both the water-stability of aggregates and the amount of water-stable aggregates in red soils. Therefore, increasing organic matter input is crucial for improving the structure of red soils.