The invention discloses a preparation method of a porous spherical compound humidifying agent, which comprises the following steps of: a, activating
zeolite for 2-3h at a temperature of 450 DEG C to obtain activated
zeolite; b, adding 30 parts by
mass of
polyacrylic acid into a
sodium hydroxide solution prepared from 15 parts by
mass of
sodium hydroxide and 100 parts by
mass of
distilled water so that
polyacrylic acid is neutralized, then adding 0.9-2.7 parts by mass of
sodium carboxymethylcellulose, 3-6 parts by mass of activated
zeolite and 0.3 part by mass of
potassium persulfate into a container containing the solution, stirring for reaction at a temperature of 70-80 DEG C; 30min later, dissolving 0.3 part by mass of
aluminium chloride in 10 parts by mass of
distilled water to obtain a solution, adding the solution in the reactor; adding 0.3 part by mass of N,N-methylenebisacrylamide, continuously stirring for reaction for 0.5-1h till a gel effect happens; and c, adding 0.9 part by mass of
sodium bicarbonate into the reactor to generate
aluminium hydroxide and
carbon dioxide, carrying out primary foaming, stirring for reaction for 0.5-1h to obtain a synthetic product; heating for 1-2h at a temperature of 150 DEG C so that the
aluminium hydroxide is decomposed and water is evaporated, and carrying out secondary foaming and
drying to obtain the porous spherical compound humidifying agent. The porous spherical compound humidifying agent has the advantages of high humidifying response speed, high
moisture content and
moisture capacity, good regulation stability, convenience in preparation, low cost, good effect, environmental friendliness and no
pollution.