Seamounts support unique biological communities and might act as important nodes of species dispersal and evolution in deep ocean ecosystems. Seamounts have been one of the few characteristic ecosystems that remain underexplored in the abyssal world. However, our knowledge of seamount animals remains very limited due to the difficulty in access to technology, resulting in controversial explanation on their fauna, biodiversity, and biogeography. There have been several hypotheses on seamount biota, including the Endemicity Hypothesis, the SourceSink Hypothesis, the Insular Isolation Hypothesis, and the Oasis Hypothesis. We summarize the pros and cons of seamount fauna and biodiversity, and put forward proposals for future investigation on seamount ecosystem.