Coptis Salisb.in China is divided into 2 groups by morphology of leaf according to Flora of China.The group with three all splited palmate leaves includes 4 species and 1 variety,which are Coptis deltoidea,C.omeiensis,C.teeta,C.chinensis and its variety C.chinensis var.brevisepala.C.quinquesecta scattered in Southeast Yunnan and C.quinquefolia distributed only in Taiwan belong to the group with five all splited palmate leaves.By using the methods of root tip squash and carbol fuchsin dyeing,we investigated the chromosome numbers and karyotypes of 5 species and 1 variety except C.quinquefolia of this genus in China,as well as C.japonica.The results are as follows:(1)The chromosome numbers and karyotypes of C.quinquesecta,C.chinensis var.brevisepala and C.japonica are reported for the first time.(2)In this genus,the basic chromosome number is x=9.Except for triploid of C.deltoidea,all others are diploids.(3)The karyotypes of all diploid species and variety of the group with three all splited palmate leaves belong to 2A type.They have similar metaphase chromosomes.In the group with five all splited palmate leaves,the karyotypes of the 2 species belong to 1A type,and the karyotypical features of the 2 species are more similar,and the sizes of chromosome are smaller than the ones of the species in another group.The similar karyotypical features support the viewpoint that the 2 groups are natural taxa respectively.(4)The degree of asymmetry of the karyotype of C.deltoidea is the highest in these 6 species and 1 variety,and its karyotype belongs to 3A type.According to the sizes of chromosomes and the geographical distribution,it is proposed that C.deltoidea be derived originally from C.omeiensis.(5)According to the asymmetric degree of the karyotype and the sizes of chromosomes,the group with five all splited palmate leaves is considered as a primitive taxon in the genus.