Genetic diversity of Bupleurum chinense DC.populations from different altitudes in Dongling Mountain district in Beijing were conducted by ISSR technology.The values of genetic diversity indexes,Shannon diversity indexes,hereditary distance,genetic differentiation coefficient and gene flow were observed.Results showed that altitude affected the genetic diversity of Bupleurum chinense DC.in Dongling Mountain district.The population at altitude 1135m showed higher genetic variation,while lower genetic diversity was observed in populations of high altitude.Hereditary distances between different populations were certainly correlated with altitude distance,that the value of hereditary distances between near altitude populations was lower.B.chinense DC.has large genetic differentiation,while a majority of genetic variation was existed in inner population.Divergent habitats and gene flow caused by different altitudes played important roles in genetic diversity of B.chinense DC.population.