The invention discloses a device for cleaning tempered glass outside a high-rise office building. The device includes a machine body, crawler belt cavities are symmetrically arranged on a left side and a right side of the machine body, a pre-cleaning cavity is arranged in the machine body, a storage cavity is arranged on an upper side of the pre-cleaning cavity, a water outlet motor is turned on so as to convey a cleaning liquid in the storage cavity into a water conveying cavity so as to convey the cleaning liquid onto a pre-cleaning block through a hose, and then clean the glass preliminarily by the pre-cleaning block, and a sprinkler sprinkles the cleaning liquid onto the g tempered glass again to perform secondary cleaning. Through triple cleaning by the pre-cleaning device, a water scraper, and the cleaning device, the device for cleaning tempered glass outside a high-rise office building can more effectively clean a dirty mark on the tempered glass.