Abstract: Twelve Populus tomentosa triploids and diploids were identified by AFLP molecular technology using a MseⅠ+3/EcoRⅠ+2 primer combination.Twelve primers with high amplified bands were selected from 38 primer combinations,including primer M-AT/E-TC with the highest ratio of polymorphic sites(32.4%) as well as primer M-TT/E-TT with the lowest ratio of polymorphic sites(15.7%).The genetic relationships among the 12 materials are relatively close.The dendrogram result of 12 clones constructed with a UPGMA method is consistent with the pedigree relationship and morphological identification,which indicates that high similarity coefficients exist in the clones with the same parents or with small morphological differences.A fingerprinting map of 12 clones has been constructed by 8 polymorphic bands selected from 3 primer combinations,which can identify the true Populus tomentosa triploids and serve as the basis for species protection.