Disclosed are an alkali-activated geopolymer coating, and a preparation method and use thereof. The alkali-activated geopolymer coating, is prepared by raw materials including the following components: an aluminosilicate mineral, an alkali activator, and a performance additive; wherein the aluminosilicate mineral comprises fly ash, slag, and metakaolin; the performance additive comprises a polymer powder, titanium dioxide, a silicone defoamer, and a water-reducing admixture; and a mass ratio of the aluminosilicate mineral, the alkali activator, and the performance additive is in a range of 100:(60-80):(4-15).