The invention provides a preparation method of layered getter. The method is characterized in that the layered getter prepared by the method has low density, irreversible water absorptivity, low coefficient of heat transfer and strong adsorptive capacity and can replace the special gas adsorbing agent of the vacuum thermal insulation board. The preparation method of the layered getter comprises the following specific steps: weighting a certain silica sol, carbon chain compound and calcium compound to prepare composite sol, then soaking a fibre board, which is prepared in advance, in the sol, sealing the container to form gel at a certain temperature, aging, cleaning, displacing the solvent, performing supercritical drying and roasting at 300 DEG C to obtain the layered getter.