The invention relates to a folding filter core with high dirt-holding capacity and an adsorbing function and a preparation method thereof. The folding filter core with the high dirt-holding capacity and the adsorbing function comprises a filter core body, and is characterized in that the filter core body is formed by filling folds of the folding filter core with a first melt-blown layer; a second melt-blown layer is arranged on the outer surface of the filter core body; an active carbon layer is arranged on the surface of the second melt-blown layer; the second melt-blown layers and the active carbon layers are arranged sequentially and alternately; the outmost layer serves as a second melt-blown layer. The defects that the folding filter core is easy to block, short in service life and weak in dirt-holding capacity are overcome, the high dirt-holding capacity of a porous filtering layer is played, and contaminants formed on the surface of a folded membrane are greatly reduced; moreover, the active carbon layers are added between the melt-blown layers in a coating manner so as to solve the micro-pollution problem of a filtered medium, so that the service life of the folding filter core is prolonged.