Abstract:The karyotypes of 9 species of Clematis in Beijing and 2 species in Northeast China were studied. Chromosome countings and karyotypes of 6 species are reported for the first time. Ten species are diploids(2n=2x=16), but C. terniflora var. mandshurica(Rupr.)Ohwi is a allotetraploid(2n=x=32). The karyotype formula of Clematis is basically 2n=2x=16=10m+2st+2-4st+2-4t(2-4SAT). In addition, the heterozygosity in the karyotypes of 4 species is discussed.