Abstract: In this study, S. sisymbriifolium Lam was chosen as test material, and its root tip was taken for chromosome section. Meanwhlie, the telomere conserved repeat sequence, 5 SrDNA and 18 SrDNA were used as probes for fluorescence in situ hybridization（FISH） to observe the position of markers and signal intensity of probes on the chromosomes. Then, the software for chromosome karyotype analysis was used to collect image and measure the chromosome length. The results showed that the karyotype formula of S. sisymbriifolium Lam was 2 n=2 x=24=24 m（2 SAT）. There were 1 pair of 5 SrDNA and 1 pair of 18 SrDNA loci on its chromosome, and telomere sequence（TTTAGGG）₆ was located at both ends of the chromosome. S. sisymbriifolium Lam was a diploid with the chromosome arm ratio 1.05-1.48. Which it was a middle centromere chromosome（m）. The ratio of the longest chromosome to the shortest chromosome was 1.42, and its karyotype asymmetry coefficient was 54.73%, belonging to the primitive type 1 A.