Abstract: During autumn 2007 and spring 2008, we surveyed 14 islands, with a total of 16 800 traps, for small mammals in Qiandao Lake, Zhejiang to determine their community distribution. The captured small mammals belonged to 11 species, 7 genera, 2 families and 2 orders，including 9 species of Murids（Muridae）, and 2 species of Soricds（Soricdae）. The results showed that the small mammals present a non-random nested pattern in assemblage on the islands. In terms of larger scale perspective, the species of high adaptability were able to adjust to the various environments, while ones of low adaptability only survived in particular circumstances. Plant species richness and habitat specificity of the species were the main ecological factors that influenced the formation of this pattern.