Abstract: Taking different ageclass rubber plantation in Xishuangbanna as study objects， the composition and stability of soil aggregates were analyzed. It was shown that under dry treatment， the amount of soil aggregates exhibited a antidoublet trend as decreaseincreasedecreaseincrease with the decrease of clay diameter. Under wet treatment， the amount in 10， 30yearold rubber plantations showed an increasedecreaseincrease trend with the decrease of clay diameter. However， 20yearold rubber plantation showed the same antidoublet trend under wet treatment as under dry treatment. For the soil aggregates with clay diameter>5 mm， its amount followed an increasedecrease trend with the increase of plantation age， and the highest amount was found in 20yearold rubber plantations. While， for the soil aggregates with clay diameter <5 mm， its amount displayed an opposite trend. The content of the waterstable aggregates with>025 mm clay diameter in 20yearold rubber plantation was greater than those in 10， 30yearold rubber plantations. The value of mean weight diameter (MWD), geometric mean diameterl (GMD) of dryaggregates and waterstable aggregates in 20yearold rubber plantation were the highest， while， the fractal dimension value (D value), of soil aggregates in 20yearold rubber plantation was small， indicating that 20yearold rubber plantation possessed the best structural stability and the strongest corrosion resistance. The rubber plantation age showed significant effect on soil aggregate stability， especially in the surface soil.

Key words: stand age, rubber plantation, dryaggregates, waterstable aggregates, fractal dimension value, stability