目的:对鬼针草染色体核型等进行来统研究，为该种鉴定、演化和良种选育等提供必要的细胞学资杆。方法:采用常规制片方法，结合显微摄影对染色体进行检测分析。结果:除观察到正常的2n=72外，还发现有2n=70的非整倍体。核型公式是K(2n)=6X=72=36m+28sm+6st+2t，染色休相对长度组成为2n=72=8L+26M₂+34M1₁ + 4S，属于"2B"型。全组染色体总长是83.41μm，长臂总长53.62μm，核型不对称系数为62.43%,染色体总体积97.17μm³。结论:鬼针草染色体的数量、形态清晰，可为进一步的深入研究打下基拙。

OBJECTIVE: To systematically study the evolution and fine seeds selection through .Bidens bipinnata chromosome number, karyotype and volume. METHODS: Sections combined with micrograph were used to analyse chromosome karyotype etc. RESULTS: Except normal diploid 2n=72, aneuploid 2n=70 was found in the same individual plant root tip. Karyotype formula was based on Levan's publication in 1964,K(2n)=6X=72=36m+28sm+6st+2t. According to the method of Kuo SR, the species chromosome based on the relative length was 2n= 72=8L+26M₂十34M₁+4S, which belonged to"2B"type according to the Stebbings karyotype classification. The total length of chromosome groups was 83.41μm, the total length of long arms 53.62μm, and from Arano's method, the AS.K% was 62.43%.The total volume of chromosome was 97.17μm³ according to De-vescovi et al. CONCLUSION: Biden bipinnata chromosome number, morphological character are clear.