Ulmus lamellose,an economically important and endangered tree species,is mainly distributed in Northeast China.It is currently subject to habitat loss,fragmentation and population decline,conservation efforts arerequired for this species.In our study,the genetic structure and differentiation of 16 natural populations of U.lamellose were evaluated using simple sequence repeats(SSR).The results showed that the high genetic diversity had occurred at the species level,low genetic diversity was present within each of the sixteen populations and significantly genetic differentiation among the populations.A clear genetic structure existed within populations ofU.lamellose.