The invention belongs to the technical field of anticorrosive paint and discloses flexible geopolymer-based anticorrosive paint and a preparation method and application thereof. The flexible geopolymer-based anticorrosive paint comprises a component A, a component B and a component C. The component A is prepared from, by weight, 15-80 parts of a geopolymer gel base material and 20-85 parts of pigments and fillers. The component B is prepared from, by weight, 40-85 parts of an alkali activator, 0-15 parts of a curing regulator, 0-6 parts of a rheological modifier and 7-45 parts of water. The component C refers to a functional toughening additive. The lexible geopolymer-based anticorrosive paint has advantages that defects of high brittleness and proneness to cracking failure of traditionalpolymer paint are overcome, and excellent flexibility of a material is achieved; in addition, the paint contains zero VOC and is low in toxicity and environmentally friendly, a coating is compact andstable, excellent corrosion resistance, permeation resistance and durability are achieved, and the flexible geopolymer-based anticorrosive paint is applicable to steel structure and concrete surface protection of infrastructures of cultural relics, buildings, municipal administration, roads, subways and the like.