The invention relates to a large wall background system of a public space. The large wall background system of the public space comprises a movable upper cover, a base clamping cloth, a lamp tube, a fixing device, a stone ultra-thin stick material and a light guide plate. The base clamping cloth is fixed to the wall surface through the fixing device, the movable upper cover is clamped with the base clamping cloth, the base clamping clothe is provided with an accommodating groove, the lamp tube is arranged in the accommodating groove, the light guide plate is arranged under the lamp tube, and the stone ultra-thin stick material is arranged on the surface of the light guide plate. According to the large wall background system of the public space, the base clamping cloth is fixed to a wall base layer by fastening bolts or rivets connected with clamping flat type corner braces, and the movable upper cover is flexibly opened to facilitate the replacement and maintenance of internal materials; as the novel natural stone ultra-thin stick material is easier to replace, the base layer light guide plate is properly handled, and the stone stick material and a light source are freely matched and replaced, the light transmission effect required for various occasions can be matched to meet the requirements of various fields in decoration industry.