The invention discloses technology for coating fume on the powder surface. The technology comprises that: oil compounds, or oil gas without complete combustion, or organic compounds or solution with high boiling point are heated for boiling or fuming, the generated vapor or fume is made to fumigate the solid powder, so that a coating membrane at the molecular level is formed on the surface of the solid powder; or the oil is incompletely combusted, the generated carbon black and fume coats the surface of the powder material. The organic compounds used for heating to generate the vapor or the fume are compounds with the boiling point of between 150 and 350 DEG C such as multi-carbon ethanol, multi-carbon carboxylic acid, multi-carbon amine, multi-carbon hydrocarbon or halogenated hydrocarbon or compound of the multi-carbon ethanol, multi-carbon carboxylic acid, multi-carbon amine, multi-carbon hydrocarbon or halogenated hydrocarbon. The use level of the coating agent is less than 0.1 percent. The method has the advantages of conveniently carrying out coating operation of the powder, and effectively achieving the aim of changing surface properties and making the powder not agglomerated without changing the composition and property of the powder; moreover, the method can carry out the coating operation of any powder in principle, particularly suitable for prevention of agglomeration of fertilizer powder products.