The invention relates to the technical field of wall structure assembly, in particular to a wall system. The wall system comprises a prefabricated foundation, prefabricated floor slabs and wall boardassemblies, wherein each wall board assembly comprises multiple prefabricated wall boards, a top bolt installing portion, a bottom bolt installing portion and side bolt installing portions are arranged at the top, the bottom and two sides of each prefabricated floor slab, multiple prefabricated wall boards form a square shape and are fixedly connected through matching of the side bolt installing portions and bolts. A basic bolt installing portion is arranged on the prefabricated foundation. Floor slab bolt installing portions are arranged on the prefabricated floor slabs. By adopting a full-dry bolt mechanical-fastened connection mode, the structural system is reasonable in stress, slab members are used as main members, the members are convenient to dismount, and the wall system is simplein design and suitable for the structural systems of fabricated buildings. All the members have no extending-out bars, production, storage and transportation of prefabricated members are facilitated,the wall system is suitable for production based on production lines, the production and transportation costs are reduced, almost no wet operation is adopted, a constriction process is simple, and theconstruction efficiency is high.