Potassium acetate/metakaolinite intercalated composites were successfully prepared by mechanical grinding at the room temperature. The structure of me takaolinite before and after the intercalation was studied by XRD, FTIR and TEM.It was found that potassium acetate was first coordinated with water molecules and then moved into the interlayer of metakaolinite by mechanical grinding, resulting in the expansion of metakaolinite layers. During the heat treatment, water volatilization also led to the expansion of metakaolinite layers. In intercalated composites, acetate ions were coordinated with the gibbsite_type layers through water molecules bridging. Besides, the hydrated K+ cation stayed near the silica-type layers with the negative charge so as to keep charge balance.