Abstract: Syringa oblata Lindl.is a native deciduous shrub species in China's temperate regions.Genetic resources of the species has been seriously degraded,remaining few scattered distributions.4 natural populations and 1 cultivated population of Syringa oblata.were analyzed using morphological markers.Morphological diversity among and within populations were analyzed based on 14 phenotypic traits,including three capsule characters,two foliage traits,five seed and four seedling traits,of 30 sample trees from each population.Variance analysis showed that there were significant variation among/within populations.The coefficient of variation(CV) was 14.25% to 29.13%,and phenotypic differentiation coefficient(Vst) ranged from 1.85% to 86.67%,the mean value of 5 populations was 43.93%.The variation within population was the main part of the phenotypic variation,variance component of within population variance was 56.06%.There is close relationship between the 10 phenotypic traits and ecological gradient variation in spatial distribution.Cluster analysis based on average taxonomic distance(Dist) of morphological traitsshowed that the 5 populations of Syringa oblata were divided into two groups and that the cultivated population was clustered into northern group.According to the research result,the lilac germplasm resources collections and protection strategy should be focused on protecting more populations as many as possible.On the other hand,integrality is also important.A selective breeding strategy should be employed not only selecting genetic variation within but also among populations.