The invention discloses an offshore satellite launching and rocket recovery platform and belongs to spaceflight and rocket launching and recovering equipment. The offshore satellite launching and rocket recovery platform is characterized in that no hulls and cabins are provided, and a deck body which is resistant to air leakage and water inflow and incapable of sinking is made by taking a buoyantfoam entity as a content and a steel mortise and tenon plate as a shell and a connecting mechanism. Modules are rapidly spliced and amplified like a foam ground mat as required by using a surface-typerigid connection mechanism to form a large or ultra-large offshore platform. The offshore satellite launching and rocket recovery platform is free of tonnage limitation and very flexible and powerfulin using function. The offshore satellite launching and rocket recovery platform is mainly composed of a submersible ballast water tank, a spatial truss and a top deck body provided with a permanentbuoyancy, can be used for fixedly or movably launching satellites and recovering rockets on the sea, can be used as a large multipurpose base and can also realize high-speed navigation to become a mobile airport/seaport dock and a super aircraft carrier. Due to the installation of an anti-sinking safety airbag, an additional sufficient reserve buoyancy is provided for the platform, and it is ensured that the platform cannot sink.