The population of Microtus fortis calamorum had entered one peak of multi-annual population fluctuation since 2005 in Dongting Lake Area.Some behavior of M.f.calamorum was observed during migration from beach and island habitat to farmland due to population outbreak,in 2007.The migration from beach and island habitat to farmland was with characteristic of looking for refuge.A majority of population died during migration while the survivals crowded many temporary colonies under stone,fallen tree,brushwood or tussock,and other coverts when they got at dike.One month later,the voles distributed into farmland and uncultivated land.They gathered in area with flourishing the weed,and fed on all eatable plant during migration,as well as the bark of blasted trees.So,they damaged the crops seriously during their migration.It will be helpful to control the harm and to learn their life history by understanding their migration behavior.