The invention discloses an attapulgite sound-insulation brick and a preparation method thereof, and belongs to the technical field of attapulgite. The attapulgite sound-insulation brick comprises the following components: high viscosity attapulgite clay, pasty attapulgite clay, glass fiber, diatomite, graphite, calcium carbonate, quartz powder and a foaming agent. The preparation method is as follows: weighing the glass fiber, the diatomite, the calcium carbonate and the quartz powder, stirring and mixing evenly, grinding, and drying to obtain a mixture I; evenly mixing the high viscosity attapulgite clay and the pasty attapulgite clay, then under stirring, adding a the mixture I, the graphite and the foaming agent, and evenly mixing to obtain a mixture II; and molding the mixture II in a die, and respectively drying, calcining, roasting at constant temperature, cooling, and cutting. The attapulgite sound-insulation brick has better sound insulation effect, also has the characteristics of stable performance, strong weatherability and long service use. In addition, the preparation method is simple and practical and has good application value.