The invention discloses a method for constructing an unsupported super-long irregularly-shaped overhanging floor. The method at least comprises the following steps of: 1, mounting steel columns and then mounting floor steel girders; 2, mounting profiled steel sheets in the floor steel girders; 3, mounting transitional reinforcing steel truss templates parallel to profiled steel sheets; 4, mounting overhanging reinforcing steel truss templates vertical to profiled steel sheets; 5, welding a plurality of lower connecting reinforcing steel bars on the overhanging reinforcing steel truss templates and the transitional reinforcing steel truss templates; 6, mounting a fast-ribbed framework at the floor steel girders and binding square steel; 7, mounting a trimming plate; 8, fixing curtain wall embedded parts on the transitional reinforcing steel truss templates; 9, binding the reinforcing steel bars on an overhanging plate; 10, casting concrete of the overhanging plate; and 11, leveling and polishing the cast concrete, initially setting and watering the concrete for curing. The method solves the construction problems of a high-rise/super high-rise super-long unsupported overhanging floor, ensures the construction speed of the floor, reduces the construction step of erecting a supporting frame, improves the construction efficiency and saves the construction cost.