The invention provides an external removable high-accuracy intelligent laser perpendicularity measuring device and a using method, belongs to the field of building construction and solves the problems of low automation degree, small application range, high using cost and the like of an existing steel column perpendicularity measuring device. According to the external removable high-accuracy intelligent laser perpendicularity measuring device and the using method, provided by the invention, a laser generator is externally arranged, and a switch and an adjusting knob are added, so that the application range of the external removable high-accuracy intelligent laser perpendicularity measuring device is amplified, and the depreciation cost of the external removable high-accuracy intelligent laser perpendicularity measuring device is reduced; by adopting a self-location distensible structure between a guide rail and an installation seat, the requirements on removability and precise location of the laser generator are met, the functions of the laser generator are greatly increased, the service life is greatly prolonged, and meanwhile, the measurement accuracy of the external removable high-accuracy intelligent laser perpendicularity measuring device is increased; a wireless transmitting module is integrated on an antenna, so that the resource waste of using a specific data line is avoided, personnel investment and the labor intensity of workers can also be reduced, and the expenditure for labor cost is reduced. The technical scheme provided by the invention has the advantages of high automation degree, wide application range, low using cost and the like, and can more meet the requirements on zero risk, high efficiency and low cost of modernized building construction.