The invention relates to a semi-submerged platform construction method and a cross bracing utilized in semi-submerged platform construction. The cross bracing is used for being connected between a port floater and a starboard floater of a lower hull and comprises a truss type cross bracing main body, first hinge seats and second hinge seats. The truss type cross bracing main body is provided with a first end and a second end, the first end is provided with first hinge parts, and the second end is provided with second hinge parts; the first hinge seats are used for being arranged on the port floater and hinged to the first hinge parts; the second hinge seats are used for being arranged on the starboard floater and hinged to the second hinge parts. According to the semi-submerged platform construction method and the cross bracing utilized in the semi-submerged platform construction, by means of the truss type cross bracing body and due to the fact that the port floater and the starboard floater are connected as a whole in a hinged mode, the folding operation during the semi-submerged platform construction is simple and easy, and after the folding operation is completed, the cross bracing can be easily removed by removing the hinges, so that the operation of carbon gouging and polishing on the connection positions of the hull can be effectively avoided, and the construction costs can be reduced.