The invention provides an assembly type steel frame filler wall system through portal steel sheet connection and a construction method of the system. The assembly type steel frame filler wall system comprises a rectangular steel frame formed by steel frame columns and steel frame beams and a precast filler wall plate, wherein the steel frame is filled with the precast filler wall plate. The upper end of the precast filler wall plate is connected with the upper steel frame beam through a portal steel sheet connecting component, and the lower end of the precast filler wall plate is fixedly weld with the lower steel frame beam. A gap between the precast filler wall plate and the upper steel frame beam, a gap between the precast filler wall plate and the left steel frame column and a gap between the precast filler wall plate and the right steel frame column are filled with a flexible material. Plastering layers are arranged on the two side surfaces of the filler wall plate and on the two side surfaces of the flexible material. The installation and construction of a filler wall do not involve any wet work, complete industrialization is achieved, the wall plate can be recycled, and the assembly type steel frame filler wall system and the method accord with the currently advocated green construction idea. Compared with an existing masonry filler wall, the masonry time and manpower input are saved, the construction efficiency is improved, installation is convenient and efficient, construction is convenient to implement, and the construction cost is reduced. The assembly type steel frame filler wall system and the method can widely used in the construction of an assembly type filler wall with the steel frame.