Diverse offshore floating platform structures are constructed for multipurpose to serve in specific environments and depths of the ocean all over the globe. The practical applications of these offshore structures demand distinct appropriate approaches platform structures, equipment filtering, and drilling/production techniques for long term stability. This study proposes a novel conceptual structure design for floating wind turbine platform to harvest offshore energy by employing the structural optimization. Topology optimization (TO) have already been practiced in numerous engineering fields to achieve the desired sustainable performance objectives such as maximizing stiffness, minimizing compliance or improving structural strength. Initially, TO suggest obtaining the novel lightweight conceptual platform structure design with minimum compliance subjected to the volume minimization. Variable density based TO method is performed for novel platform design by removing the unnecessary material from the design domain under the applied wind turbine and hydrodynamic and mooring lines forces. The obtained topological optimized floating platform structure is a lightweight design structure that also makes sure long term structure strength integrity.