Attapulgite clay is well-known as a “universal soil” and has been widely used in industrial production. In our study, it was compounded with magnesium hydroxide—an alkaline medium commonly used for deacidification of paper—to produce a new composite material. After several trials, it was determined that the magnesium hydroxide loading in this composite was at most 25%. The dispersion of the composite was confirmed using transmission electron microscopy (TEM). Physical property analysis showed that attapulgite clay was a good carrier for the deacidification material, and verified the formation of the composite. Subsequently, this composite material was applied to paper deacidification. Through comparison, it was found that the deacidification performance of the composite was superior and that the properties of the paper were significantly enhanced after deacidification.