Abstract: Rumen ciliate species and composition were surveyed on Murrah Buffalo, and Xilin Buffalo, in Guangxi, China. The concentrations of volatile fatty acids of rumen fluid were detected. As a result of survey, 17 genera including 63 species with 25 formae were identified. Total number and average genus number of rumen ciliate in this survey were more than those in 8 ruminants which were studied long time ago. The composition of species was similar to that of buffalo rumen in Southeast Asia. A new species of the genus Entodinium was recognized from Xilin Buffalo, and then it was described as Entodinium biconcavum sp n. This new species was not detected before. 13 genera including 54 species with 20 formae, and 16 genera including 45 species with 11 formae were identified from Xilin Buffalo, Murrah Buffalo, respectively. The average ciliate density was estimated as 2.13×10⁵/mL in Xilin Buffalo, 3.43×10⁵/mL in Murrah Buffalo. The genus Entodinium was recognized with highest frequency of appearance in Xilin Buffalo and Murrah Buffalo rumen ciliate, but that of Xilin Buffalo was different from that of Murrah Buffalo. Other genera were not the same, which was related to buffalo kept in environment and feeding system. The total volatile fatty acids concentration of rumen fluid of Xilin Buffalo, and Murrah Buffalo were 75.60 mmol/L, and 58.74 mmol/L respectively. The concentration of acetate acid of rumen fluid was highest among VFAs, suggesting that rumen fermentation was typical forage fermentation.