An assembled integral type shear wall structure system is formed by hoisting and assembling prefabricated composite wallboards into a whole in a construction field. A board body of each prefabricated composite wallboard is provided with a structure layer, a thermal insulating layer and a protective layer in sequence from inside to outside, wherein the structure layer is internally provided with a reinforcing cage, the thermal insulating layer is an extruded polystyrene foamed plastic board, concrete of the protective layer is internally provided with a reinforcing mesh, and anchor bolts are connected among the structure layer, the thermal insulating layer and the protective layer in point distribution. Vertical seams and horizontal seams of a prefabricated composite wall adopt self waterproof structure, thus solving the common quality problems such as leakage, cracking and the like in the traditional process. The prefabricated composite wall simplifies construction process, improves construction speed and reduces construction cost. Moreover, prefabricated products of factories have consistent specifications and quality, so that construction quality of building structure can be fully ensured, the industrialization, standardization and generalization of the building wall are realized, and the assembled integral type shear wall structure system can be widely applied in the construction of reinforced concrete buildings in the construction industry.