Investigated in this paper was the karyomorphology of Calathodes oxycarpa (Ranunculaceae)．The resting nuclei and the prophase chromosomes were categorized to be complex chromocenter type and interstitial type respectively；the metaphase chromosomes were relatively large and belonged to Ranunculus-type (R type)；the karyotype was formulated as  2n=16=8sm+8st(2sat)．Based on the results，combined with the evidence from comparative morphology and palynology，the genus Calathodes is considered to be most closely related to Trollius and Megaleranthis．  It is not reasonable to put them in different tribes or subfamilies．