The invention relates to a preparation method of organic sepiolite, which is characterized by comprising the following steps: (A) placing1,6-hexanediamine and epoxy chloropropane into deionized water, stirring for 4h at 40 DEG C; (B) adding triethylamine after the reaction of the (A) is finished, reacting for 10h at 60 DEG C, then distilling to remove solvent, preparing hydrophilic quaternary ammonium salt; (C) adding activated sepiolite and hydrochloric acid into deionized water, stirring and reacting for 2-4h at 50-60 DEG C to obtain sepiolite suspension liquid acidized by the hydrochloric acid; and (D) adding the hydrophilic quaternary ammonium salt obtained by the (B) into the sepiolite suspension liquid obtained by the (C), stirring and reacting for 4h at 50 DEG C, filtering, drying to obtain the organic sepiolite. Compared with the prior synthesizing and modifying method, the invention has the advantages that: (1) the specific surface area of the organic sepiolite is larger thanthat of the sepiolite raw material; (2) the interlamellar spacing of the organic sepiolite is enlarged and the activity is improved; and (3) the absorption capacity of the organic sepiolite is betterthan that of the sepiolite raw material.