Abstract: In this paper the chromosome observation of nine herbage species of Melilolus were reported, in which three species (M. allus var. annua, M. officinalis var. annua and M. caerules)have not been reported before. By the comparison, it is indicated that the karyotypes are much the same between these species and they all contain 2n=16 chromosomes. The chromosome morphological structures of these species are different from that reported previously by Kita because of the differentiation in geographical distribution. It may he considered that a poonible approach for the evolution of the karyotypes in the Melilotus probably is mainly due to the chromosome structure, rather than polyploid.