Abstract: The blood samples of 19 individuals of Sichuan snub-nosed monkey (Rhinopichecus roxellana) from two different geological regions were investigated in this study.All of forty-four genetic loci surveyed were monomorphic.Its mean heterozygosity,a measurement of genetic diversity,was zero.Considering the larger size of population and better living state of Sichuan snub-nosed monkey than Yunnan snubnosed monkey (R.bieti),we inferred that Sichuan snub-nosed monkey might have experienced previous bottleneck,and after this,its population recovered.The speculation is also supported by geological data.