Offshore platform module demounting and mounting system

The invention relates to an offshore platform module demounting and mounting system. The offshore platform module demounting and mounting system is characterized by comprising a barge body, a stem, a stern, a living building module, two cargo booms and slide rails; the stem and the stern are integrally formed with the barge body, and the living building module and the cargo booms are arranged on the upper portion of the barge body; the living building module is located on one middle side of the barge body, and the symmetrically arranged cargo booms are arranged one side of the stern; the slide rails are arranged on the stem and the stern. Demounting and mounting of upper modules of an offshore jacket platform, an SPAR, a TLP (tension leg platform) and a semi-submersible platform can be realized, the system is simple in structure, convenient to built, economical and practical and capable of being widely applied in the offshore platform mounting fields.