The utility model relates to a novel platform, particularly to a separating base self-lifting platform. The platform is composed of a self-lifting main platform, a base supporting structure, a butting guiding device and a ballasting system. The platform is divided into two big separate bodies with floating performance. When the platform is operated, the base platform can be automatically formed by butt joint up and down on the sea. The structure of the self-lifting main platform is essentially the same as the conventional self-lifting main platform. Each up-down spud leg is provided with a guide wheel and a guide sleeve. The base supporting structure is provided with a box body and a fixing spud leg corresponding to the up-down spud leg to be welded into a rigid whole. The butting guiding device guides the up-down spud leg and the fixing spud leg to position exactly through a guide cable. The ballasting system controls the sinking and floating of the base supporting structure, and the matching operation can realize the butt joint and disassembly of the platform on the sea. The utility model can be used for a new-building platform and can also be used for the deep water modification of the existing self-lifting platform.