Abstract: Camellia nitidissima Chi (Theaceae)is an important horticultural and economic species,distributed in a narrow region of southern China and northern Vietnam.One hundred and twenty-six individuals from four populations of C.nitidissima were analyzed by ISSR (inter-simple sequence repeat) markers to detect the genetic variation among and within populations.Twelve primers produced a total of 105 scorable markers,of which 79 (75.24%) were polymorphic.As analyzed by the software POPGENE and NTSYS,the genetic diversity of C.nitidissima was high,with Nei’s gene diversity of 0.2302 and Shannon’s Information Index of 0.3502.In contrast,the genetic diversity with each population was low.The coefficient gene differentiation (G_st) was 0.5752,indicating more differentiation among populations than within populations.UPGMA cluster based on Nei and Li genetic similarity formed 4 clades correspongding to the four populations.The Mantel test revealed that a positive correlation (r=0.68261,P=1.0000) existed between genetic distance and geographical distance.