Abstract: Eight pairs of AFLP primers were screened out and used for the analysis of 28 main poplar varieties in Liaoning Province. The results showed that 983 fragments were generated totally. 972 of which were polymorphic with a polymorphism percentage of 98.75%. All these date indicated that considerable genetic difference existed among varieties and clones at DNA level. The genetic differences among testing varieties were great, genetic distance among 28 materials tested was 0.468 7-0.996 0. P.× Liaoningensis and P.× ′Liaoyu-3′ (0.468 7), P.× canadensis ′014′and P.× canadensis ′Guariento′ (0.475 5), P.× canadensis ′177′ and P.× canadensis ′zhongliao 1′ (0.493 3) had smaller genetic distance, indicated that close genetic relationship. Using UPGMA cluster analysis from AFLP date, similarity coefficient was 0.369 0-0.625 8 and materials tested were classified into 8 categories at similarity coefficient of 0.533. When the similarity coefficient at 0.559, 15 varieties of 3-class can be divided into 5 groups. The classification results were basically consistent with growth performance. P.× Liaoningensis and P.× ′Liaoyu-3′ had the highest similarity coefficient of 0.625 8. The findings verified that they had the closest genetic relationship at molecular level.