Abstract: A detailed study on offshore floating wind turbines, the working principle of SPAR floater and the conceptual design of SPAR floating platform used for floating wind turbines are presented. This study discusses the preliminary design methodology of SPAR floating structure for the DOWEC 6 MW off shore wind turbine. Structural design and stability is done analytically as per the API RP 2A. Buckling stress analysis is examined with ANSYS Software. Heave and pitch motions have been chosen as the critical design parameter. And the hydrodynamic numerical simulations have been performed using panel method.