Deepwater net cage lifting system

The invention relates to a deepwater net cage lifting system comprising a sinker, a floater, a gas filled pipeline and multiple sinker lifting devices, wherein the gas filled pipeline is used for connecting the sinker and the floater. The sinker lifting devices are used for hanging the sinker under a net cage through mooring ropes, and the floater floats on the water surface. The floater comprises a shell, a gas generating device and a reversing valve, wherein the gas generating device comprises a gas bag and heaters. The net cage submerges through the mode that the reversing valve is controlled to inject water into the sinker and floats upwards through the mode that the gas generating device is controlled to enable the gas bag to be swelled to extrude gas, so that the gas is injected into the sinker. The deepwater net cage lifting system can freely control the net cage to float upwards or submerge remotely so that the net cage can resist to wind waves and can be prevented from being turned sideward in the process of upward floating or submerging. In addition, new energy is comprehensively used for generating power and for supplying electric energy to the deepwater net cage lifting system, and the utilization rate of the energy is improved.