The invention discloses a marine buoy with a function of automatic avoidance collision. The marine buoy comprises a buoy float, wherein a mast is mounted on the buoy float; the mast is connected with a transmission device located in the buoy float; the transmission device is connected with a first motor; a roller is mounted at the top of the mast; a lead wire is mounted in the roller; one end of the lead wire is connected with a sail located on the mast, and the other end of the lead wire is connected with wires which are automatically taken up and paid out and are located on the buoy float; the wires which are automatically taken up and paid out are connected with a controller located in the buoy float; and a plurality of infrared inductors are mounted on an external wall of the buoy float in a circumferential direction, and are connected with the controller. According to the marine buoy disclosed by the invention, when a ship sails to the buoy float, the infrared inductors detect the sailing direction of the ship, the controller controls the motor to rotate according to the detected information, the sail is adjusted to an appropriate angle, and the wires which are automatically taken up and paid out take the wires up to suspend the sail, so that the buoy float sails in the direction away from the ship, the marine buoy is prevented from being damaged or scrapped due to collision, and the cost and the difficulty of operation and maintenance of the marine buoy are reduced.