The invention discloses a floating type offshore wind power assembly platform, which comprises a platform, wherein a left ballast tank, which is higher than the platform, is arranged on a left board of the platform, a right ballast tank, which is higher than the platform, is arranged on a right board of the platform, the platform is provided with a bottom ballast tank, a transportation guide rail is arranged on the platform, a fixed jacklift used for fixing a fan tower drum is arranged between the left ballast tank and the right ballast tank on the platform, a left board side fixing support is arranged on the inner side of the upper part of the left ballast tank, a right board side fixing support is arranged on the inner side of the upper part of the right ballast tank, a fixed lifting bracket used for fixing the fan tower drum is arranged between the left board side fixing support and the right board side fixing support, and cranes are both arranged on the left bulkhead and the right bulkhead of the platform. The floating type offshore wind power assembly platform has the advantages of large structure size and good stability, and can normally work under a certain storm condition; furthermore, the offshore construction difficulty is reduced, the construction period is shortened, the flexibility of construction is improved, and different schemes can be adopted for installation according to different wind field conditions.