Bats belonging to Microchiroptera have been known one of the most gregarious mammals. They rely mainly on acoustic signals to communicate in darkness and maintain their social structures. Some species demonstrate a diverse repertoire of syllables, but few studies have conducted on their social calls for specific species. We recorded the social vocalizations of captive adult Murina leucogaster and analyzed its spectral characteristics based on the shape of sound wave in the spectrogram. Communication calls were grouped together into preliminary vocalization types based on their visual similarity in sonograms, and then we performed a principal component analysis (PCA) and a discriminant function analysis (DFAs) to confirm the preliminary classification. The results show that M.leucogaster possess a rich repertoire of social vocalizations with sixteen distinct syllable types. These syllables were further categorized into 13 simple syllables and 3 composite syllables, and most of them had multiple harmonics. Simple syllables can be classified into 9 frequency modulation syllables, 2 quasi-constant frequency syllables and 2 noise burst syllables. Composite syllables consist of simple syllables conjoined without any silent interval. Maximum frequency of fundamental frequency, bandwidth of fundamental frequency and duration were highly correlated to the types of frequency modulation syllables. These results provide a basis for future studies not only of the behavioral significance of vocalization, but also of the neural basis of vocal communication in the M. leucogaster.