The invention discloses a method for preparing nano attapulgite/silicon dioxide composite materials. Firstly, attapulgite is added into de-ionized water to prepare suspension liquid containing 2-20 percent of solid; secondly, sodium silicate solution (mass concentration: 5-30 percent) and acid solution (mass concentration: 3-30 percent) are prepared; finally, the achieved nano attapulgite/silicondioxide composite materials are filtered, the soluble salt is repeatedly washed by de-ionized water, dried and porphyrized. On the precondition that the clavated structure of the nano attapulgite is not damaged, the method adopts chemical precipitation to generate nano granular silicon dioxide in situ in the nano attapulgite dispersed liquid, and a spherical-clavated composite reinforcing material is prepared, thereby, the surface properties of the attapulgite is changed, the brightness of the nano attapulgite is improved, and the field of attapulgite minerals deep-processing and comprehensive utilization is expanded; the preparation process is simple and the production cost is relatively low.