Recovery device and recovery method for offshore launching test platform

The invention relates to a recovery device and a recovery method for an offshore launching test platform, and belongs to the technical field of deep sea launching platform recovery. The recovery device comprises recovery units which are in one-to-one correspondence with the sub-platforms in the test platform; each sub-platform comprises a bottom platform and a top platform; the recovery unit comprises a connecting shell mounted between the bottom platform and the top platform; a plurality of storage grooves are formed in the connecting shell, openings are formed in the positions, corresponding to the storage grooves, of the outer side face of the connecting shell, and the openings are sealed through cover plates. A fuel gas generator and an air bag assembly are arranged in each storage groove. The air bag assembly is connected with the connecting shell through a connecting rope. After the fuel gas generator ignites to inflate the air bag assembly, the air bag assembly stretches out of the connecting shell to