AbstractThis paper studied on species diversity in ecotone of coniferous and broad-leaved forest community in Russia plain．The results show that species diversity in this region is similar to those in most other ecotones.The species diversity in the ecotone(mixed coniferous and broad-leaved forest)is higher than those in contiguous communities(coniferous and broad-leared forest) The composition structure of mixed coniferous and broad-leaved forest communities represents its transition feature．In this ecotone，the higher diversity can’t demonstrate the increasing of the community stability．Therefore。the correct results rely on the integrated consideratiou of more indexes when the rehtionship between species diversity and community stalfility is discussed．