The invention provides a counterweight overturning type wax scraper for an external floating roof storage tank. The counterweight overturning type wax scraper comprises a wax scraping plate, connecting support lugs, scraper supports and counterweight stress application mechanisms, each counterweight stress application mechanism comprises a link mechanism, a support rod and a balancing weight, thelink mechanism is of a parallelogram structure capable of swinging front and back, the support rod is connected with the rear vertex angle of the top edge of the link mechanism through a pin, the balancing weight is arranged at the tail end of the support rod, and front vertex angle of the bottom edge of the link mechanism is connected with the corresponding scraper support through a pin; and square holes allowing inserted placement of the connecting support lugs are formed in the tail ends of the scraper supports, the tail ends of the connecting support lugs are fixed on the wax scraping plate, and limiting mechanisms are arranged on the wax scraping plate. The contact surface of the wax scraping plate and the wall of the external floating roof storage tank is line contact, the wax scraper has large shear force and has larger positive pressure on the wall of the storage tank under the condition that weight of the counterweight is not changed, and the problem of poor wax scrapping performance of the wax scraping plate of a heavy hammer type wax scraper is effectively solved.