Abstract: Dynamics of soil seed bank of exotic weed Mikania micrantha populations in three communities in Neilingding Island were studied. The results showed that densities of soil seed bank in upper layer soil were higher than that in lower layer soil. With the increasing of soil depth, vigor seed decreased. Seedlings mainly came from the seeds in upper layer soil. Seed production and soil seed bank of the three populations of M. micrantha were different due to different succession stage of the three communities. Density of seed bank in community in later succession stage was lower than that of in early succession stage of community.