In recent years, our team made the following scientific achievements: (a) discovered the vocalization characteristics/biological sonar vocalization mechanism and environmental adaptability of acoustic signals of small dolphins, such as Indo-Pacific humpback dolphins (i.e., Chinese white dolphins), and large whales，and developed passive acoustic monitoring on cetaceans in the South China Sea; (b) discovered the species composition, distribution patterns and threats to marine mammals in the northern South China Sea, and recorded the presence of Indo-Pacific humpback dolphins in waters southwest of Hainan Island, and sperm whales and other deep-diving and off-shore cetaceans in the northern South China Sea; (c) established preliminary surveys of the geographical pattern and population relationship of the Indo-Pacific humpback dolphin population in Chinese waters; (d) discovered the phylogenetic evolution of some marine mammal species and the adaptive evolution of their aquatic life, biosonar and deep-diving behaviors.