Giemsa C-banding patterns and karyotype of chromosomes were analyzed in the root-tip cells of diploid Thinopyron elongatum. A modified seed germinating method was developed for obtaining the C-banding patterns in diploid Thinopyron elonggatum. The results of The C-banding analysis showed the significant differences among the seven pairs of chromosomes in diploid Thinopyron elonggatum. The intensive C-bands were stained steadily on the intercalary, terminal, subcentromeric and centromeric regions of Chromosomes. We found that there are three pairs of metacentric chromosomes and four pairs of submetacentric chromosomes in diploid Thinopyron elonggatum. The karyotype formula is 2n=2x=14=6m+8sm. Present results provided a basic cytological data and will be useful for the further studies in Thinopyron elongatum.