With multi-variant morphological measurement data, the author used three multivariation analysis methods (cluster analysis, principal component analysis and discriminant analysis) to study the morphological variations among five geographic populations of Paphia undulata in south China: Dongguan and Zhanjiang (Guangdong), Xiamen (or Amoy, Fujian), Haikou (Hainan), and Beihai (Guangxi). Results indicate that populations of Dongguan, Xiamen, Zhanjiang and Haikou were morphologically grouped together, leaving Beihai population alone. Significant differences were found among the five populations (P0.01) by discriminant analysis. The Mantel matrix tests of geographic and Euclidean dis- tances indicated no significant relationship (r = 0.0822, P = 0.3820). As the Beihai population was shown quit different from other ones, it may have been generate a new subspecies. In general, the morphological variations of P. undulata may be resulted from a joint effect of genetics and environment. Therefore, more future works are called in molecular genetics for providing scientific basis for germ plasm resources protection and genetic breeding.