The invention discloses a building paint special purpose anti-corrosion additive. The building paint special purpose anti-corrosion additive comprises, by mass, 38 to 52 parts of vinyl methoxy silane,32 to 45 parts of vinyl trimethoxy silane, 28 to 35 parts of vinyl epoxy silane, 12 to 25 parts of lithium polysilicate, 8 to 12 parts of sodium polysilicate, 1 to 11 parts of titanium dioxide particles, 2 to 12 parts of toluene and 1 to 5 parts of methyl isobutyl ketone. The additive has very high corrosion resistance and can be prepared according to a simple formula.