The Xenopeltis unicolor is a vertebrate wild species belonging to the Xenopeltidae, Colubridae, Reptilia. Xenopeltis unicolor is a widely distributed species in the delta of the Mekong River, Vietnam. The study on biological traits, however, of this species is unknown so far in this study region. Therefore, the study discussed about its biological characteristics and this paper also published the initially biological results, providing scientific bases to diversity conservation plan of Xenopeltis unicolor in the study region are necessary. The results indicated that snout-vent length of adult females were 663.8mm and 638.9mm in adult males. The diet of this species is very wide, but most of mouse and perch with high frequency in the stomach contents of snakes. Testicular mass is approximately 0.67 percent, and ovarian mass of 1.25 percent, compared to body mass of males and females, respectively.