The invention discloses an aluminized protective coating as well as a preparation method and an application thereof. The aluminized protective coating is mainly prepared from metallic nickel, zirconia and a binder in the volume ratio being (0.7-1.3):(0.7-1.3):2. The aluminized protective coating is prepared from common and easily-obtained raw materials and is low in price and low in cost; all that is required for solid powder aluminizing at 900 DEG C or below is to perform coating of 2-3 layers; protective requirements during solid powder aluminizing with the aluminizing temperature in the range of 600-1,020 DEG C can be met; the aluminized protective coating is easy to clean after aluminizing is completed, can be broken to be separated from a protective matrix and is free of residues; the raw materials of the protective coating are neutral, do not corrode the protective matrix and cannot react with a high-temperature alloy matrix; and the protective coating cannot be peeled off automatically after being aluminized, can be physically separated from an aluminizing agent and cannot pollute the aluminizing agent.