The invention discloses an assembled simple support box beam structure of a PVA fiber cement base composite material and a manufacturing method. The assembled simple support box beam structure comprises an outer wrapping layer, a lining layer, embedded parts, pulled steel bars, stirrups, a corrugated pipe, a telescopic steel pipe, ordinary concrete, pressed steel bars and prestress ribs. The outerwrapping layer and the lining layer are formed by splicing PVA fiber cement base composite material plate sections. The embedded parts are arranged on the inner surface of the outer wrapping layer and the outer surface of the lining layer and are steel T-shaped anti-shear connection pieces. The pulled steel bars and the stirrups are arranged inside the outer wrapping layer and the lining layer. The pressed steel bars and the prestress ribs are arranged in the ordinary concrete. The telescopic steel pipe is arranged between the outer wrapping layer and the lining layer. The assembled simple support box beam structure can serve as a template of a box beam to be used at the prefabrication stage; and in addition, after the box beam is formed, the assembled simple support box beam structure can serve as a protection layer of concrete in the box beam, the ductility of a bridge can be effectively improved, and the crack and shock resisting performance and the like of the bridge are improved.