Seabed natural gas collecting device and method with built-in buoyancy tanks and hot water pipelines for heating

The invention discloses a seabed natural gas collecting device and method with built-in buoyancy tanks and hot water pipelines for heating, and belongs to the technical field of natural gas collection. The seabed natural gas collecting device comprises a primary boat and a hollow natural gas collecting hood, wherein a natural gas collecting and storing device is arranged on the primary boat and connected to the top of the natural gas collecting hood by a gas collecting pipeline; the natural gas collecting hood is connected to the bottom of the primary boat by a water isolating pipe; a gas collecting pipeline is arranged in the water isolating pipe; anchoring systems are arranged around the bottom of the natural gas collecting hood; pressure adjusting systems are arranged on the bottom of the natural gas collecting hood; propelling systems are arranged on the outer wall of the natural gas collecting hood; a density adjusting system is arranged on the side wall of the natural gas collecting hood; and a temperat