The present invention provides a suspension comprising aluminum hydroxide and magnesium hydroxide and a method of preparing the same. The aqueous suspension composition according to the present invention ensures an excellent sedimentation rate by using a mixed suspending agent with a specific composition, so that insoluble aluminum hydroxide and magnesium hydroxide do not easily settle, do not form a cake, and are easily redispersed. Since the aqueous suspension composition having an excellent sedimentation rate has not only physical stability, but also forms a homogeneous dispersion system, the reproducibility or effectiveness of bioavailability may be ensured. In addition, the aqueous suspension composition according to the present invention provides an excellent texture, and thus patient compliance increases.
