Abstract:In Cephalotascus sinensis (Rehd. et Wils. ) Li the somatic chromosome number was found to be of 2n=24. Eleven pairs of chromosomes possessed their centromeres at median or median-submedian regions. The shortest pair of chromosomes was the SAT chromosome which possessed their centromeres at the submedian regions. The sex chromosomes were demonstrated by the Giemsa C-banding technique. The sexual determination mechanism of female was WZ type (2n=24=22A+WZ), and that of male was ZZ type (2n=24=22A +ZZ).