The invention discloses a blocking power positioning floating bracket installation technology of a large marine structure. The blocking power locating floating bracket installation technology comprises the steps of (1) transporting blocking to a marine platform installation site and then carrying out power positioning in-place exercise; (2) enabling a ship to gradually approach a jacket by virtue of a power positioning system, positioning a chip through a position reference system and guiding the chip to smoothly enter a notch of the jacket through a ship entering guide arranged on the chip; (3) enabling the ship to advance to a final docking position in the notch of the jacket, adjusting the ballast on the chip and transferring the blocking to the jacket; and (4) further adjusting the ballast of the ship to an exit draught position and then making the ship quit from the jacket to complete blocking power positioning floating bracket installation operation. The large marine structure can be installed under the conditions of any weather window and operating water depth, and furthermore, the installation efficiency on the large marine structure under a severe sea condition is greatly improved.