The invention relates to a fluorosilicone benzoxazine block copolymer and application thereof and belongs to the technical field of macromolecular compounds and application. The fluorosilicone benzoxazine block copolymer is prepared by taking unsaturated bond containing benzoxazine and double-ended hydrogen polysiloxane as monomers, taking a platinum catalyst or/and chloroplatinic acid as a catalyst and reacting at the temperature of 60-110 DEG C. The fluorosilicone benzoxazine block copolymer is crosslinked and solidified under certain conditions to form an oil-water separation membrane, and the oil-water separation membrane has low surface energy and excellent hydrophobic property and oleophylic property. By adopting the prepared fluorosilicone benzoxazine block copolymer, the oil-water separation membrane can be obtained, and the oil-water separation membrane has low surface energy and excellent hydrophobic property and oleophylic property; a water contact angle is more than 155 degrees, and an oil contact angle in the air is close to 0 degree.