The invention discloses a DGC board-type assembled house system and a construction and a manufacturing method thereof. A basic unit of the system is formed by floor slabs and wallboards which are combined and assembled in a modularized manner; the wallboards are prefabricated composite boards, each wallboard mainly consists of a light-steel frame, a peripheral guard board, a sandwich insulation layer, a heat insulating layer and turnbuckles, and different wallboard standard modules such as in-line wallboards, L-shaped wallboards, T-shaped wallboards and cross-shaped wallboards are adopted and freely combined; the floor slabs are prefabricated composite boards, the floor slabs are used as foundation slabs, floor slabs or roof slabs of the DGC board-type assembled house system, and vertical connection between the floor slabs and the wallboards in the system consists of combined connection of lateral connection of horizontal M-shaped steel, M-shaped chord members and square steel pipes through tapping screws and vertical connection of the turnbuckles in trusses. According to the DGC board-type assembled house system and the construction method and the manufacturing method thereof, the structure is simple, the construction speed is fast, the construction period is reduced, the cost is low, and the defects of single structure, complex installation process and high labor cost of the existing assembled house structure can be overcome.