The present invention discloses a method for preparing a full-body marble-patterned glass mosaic, comprising mixing a glass powder with an additive to obtain a mixture; adding water to the mixture and mixing thoroughly; granulating and sieving to obtain base clay body powder; mixing a colorant and a flux according to a specific ratio to obtain a colorant mixture in powder form; distributing the base clay body powder and the colorant mixture into multiple layers via a mold; press-molding to obtain a clay body; firing the clay body to obtain the full-body marble-patterned glass mosaic. Accordingly, the present invention provides a full-body marble-patterned glass mosaic prepared by the method described above. The glass mosaic of the present invention has a strong layering texture and a well-defined structure, and it faithfully resembles the pattern and texture of natural marble.