Abstract: This paper reported twenty-five species of rodents collected in Zhejiang. They belong to 7 families and 14 genera. The predominant species are from Muridae. Eight species are new recorded. Study shows that the species number is decreased with the increasing population density. The author comes to the conclusion that it is the ecological inequilibrium caused by human activities which led to these changes.

Key words: Exotic pines, Decline disease, Environmental condition, Cause of disease