Abstract: The individual growth,morphology and population biomass of Pennisetum centrasiaticum clones at two different habitats of farmland-sand dune ecotone on Keerqin sandy land of Inner Mongolia were compared in this study.P. centrasiaticum clones had significant morphological plasticity and different biomass distribution pattern at different habitats.Compared with P. centrasiaticum clones on semi-fixed sand dunes,those on farmland-sand dune transitive zone had a greater leaf elongation,longer rhizomes and internodes,more adventitious buds,larger amount of biomass,and deeper distribution of underground biomass,which were closely associated with the losse texture of the upper soil and the rather favorable water condition of the lower soil.It is believed that the population can well adapt itself to the farmland-sand dune ecotone habitats,and thus,play an important role in fixing mobile sand in succession of arenaceous vegetation.