A floating platform for high-power wind turbines, of the type including a resistant base, which has a mooring line at each corner through which it is anchored to the seabed, being maintained in a semi-submerged position, on the base of which a central cylinder and at least four outer cylinders are constructed, all of them made of reinforced concrete, the central cylinder of which extends vertically in the wind turbine tower, characterised in that it comprises: - a concrete substructure, forming the base of the platform, and consisting of: ∘ a square lower slab forming the base of the platform; ∘ a series of beams (3, 31) providing structural stiffness to the slab, being attached to and above the same, at the same time that they brace the cylinders (2, 21) from below, by remaining embedded in them; ∘ five hollow reinforced concrete cylinders (2, 21) distributed at the corners and the centre of the lower slab, executed by means of sliding from the slab, once this has been executed and stiffly joined forming a single body with said slab and with beams (3, 31) which join them; and - a metal superstructure, which supports a concrete substructure and forms the base for connection with the wind turbine tower, being coupled at the centre thereof, consisting of: ∘ metal covers (5, 51) covering each of the peripheral cylinders and the central cylinder; ∘ vertical pillars (6, 61) which come out from the covers (5, 51) located on the cylinders (2, 21), which remain linked together by means of beams (7, 71); and ∘ corresponding systems of beams (7, 71) which join, on the one hand, the vertical pillars of the four outer cylinders to each other, and, on the other, diagonally join each column to the central column and to a central metal element, whereon the base of the wind turbine tower is secured, transmitting the load from the base to each of the four pillars, wherein these radial beams remain embedded. - a concrete substructure, forming the base of the platform, and consisting of: ∘ a square lower slab forming the base of the platform; ∘ a series of beams (3, 31) providing structural stiffness to the slab, being attached to and above the same, at the same time that they brace the cylinders (2, 21) from below, by remaining embedded in them; ∘ five hollow reinforced concrete cylinders (2, 21) distributed at the corners and the centre of the lower slab, executed by means of sliding from the slab, once this has been executed and stiffly joined forming a single body with said slab and with beams (3, 31) which join them; and ∘ a square lower slab forming the base of the platform; ∘ a series of beams (3, 31) providing structural stiffness to the slab, being attached to and above the same, at the same time that they brace the cylinders (2, 21) from below, by remaining embedded in them; ∘ five hollow reinforced concrete cylinders (2, 21) distributed at the corners and the centre of the lower slab, executed by means of sliding from the slab, once this has been executed and stiffly joined forming a single body with said slab and with beams (3, 31) which join them; and - a metal superstructure, which supports a concrete substructure and forms the base for connection with the wind turbine tower, being coupled at the centre thereof, consisting of: ∘ metal covers (5, 51) covering each of the peripheral cylinders and the central cylinder; ∘ vertical pillars (6, 61) which come out from the covers (5, 51) located on the cylinders (2, 21), which remain linked together by means of beams (7, 71); and ∘ corresponding systems of beams (7, 71) which join, on the one hand, the vertical pillars of the four outer cylinders to each other, and, on the other, diagonally join each column to the central column and to a central metal element, whereon the base of the wind turbine tower is secured, transmitting the load from the base to each of the four pillars, wherein these radial beams remain embedded. ∘ metal covers (5, 51) covering each of the peripheral cylinders and the central cylinder; ∘ vertical pillars (6, 61) which come out from the covers (5, 51) located on the cylinders (2, 21), which remain linked together by means of beams (7, 71); and ∘ corresponding systems of beams (7, 71) which join, on the one hand, the vertical pillars of the four outer cylinders to each other, and, on the other, diagonally join each column to the central column and to a central metal element, whereon the base of the wind turbine tower is secured, transmitting the load from the base to each of the four pillars, wherein these radial beams remain embedded.