Abstract:The demography history and genetic divergence of alpine shrub Sibiraea laevigata were studied with 13 populations (139 individuals) collected in the whole distribution area in China, using the intron of chalcone sythase (CHS) as molecular marker. A total of 29 haplotypes were identified in S.laevigata, indicating high haplotype diversity and nucleotide diversity which were 0.924 8 and 0.007 545, respectively. Bayesian calculation illustrated the genetic divergence in S.laevigata began at around 4.37 Ma, proved that the uplift of Qinghai-Tibetan Plateau triggered the genetic divergence. Neutrality test and mismatch distribution analysis consistently indicated the populations of S.laevigata had experienced recent population expansion at about 55.8 ka.