A preparation method of a zirconium-titanium-based alloy embedded aluminized layer includes putting a zirconium-titanium-based alloy and an aluminiferous penetrant into a mould from bottom to top in a sequence of a first penetrant layer, a first zirconium-titanium-based alloy, a second penetrant layer, a second zirconium-titanium-based alloy and a third penetrant layer, and compacting to obtain a mixed sample; sequentially covering a surface of a mixed sample with activated carbon powder and alkali metal halide, and then carrying out heating and cooling treatments to obtain a zirconium-titanium-based alloy embedded aluminized layer. The preparation method does not need to adopt a special heating furnace or carry out heat treatment under a vacuum condition in an actual application, which simplifies operation process and condition and is suitable for large-scale production and application due to few technical difficulties and low equipment investment cost.