Abstract: A seafloor observation network-based subsurface buoy device with real-time power supplying and high-speed data transmitting is provided. The subsurface buoy device includes a seabed base deployed on the seafloor and a vertical mooring system connected to a bottom surface of the seabed base to extend to the sea surface. The seabed base serves as a gravity anchor to enable the subsurface buoy device to be positioned stably at a layout site, and is further used for obtaining power supply of the subsurface buoy device from a junction box of a seafloor observation network. The seabed base also sends the management and control commands from the junction box to the vertical mooring system, and transmits the data collected by the vertical mooring system back to the junction box in real time.