The invention discloses a method for improving the surface quality of high-strength and weather-resisting H-shaped steel. In a profiled blank continuous casting process, the straightening temperature of a casting blank is 830 DEG C to 900 DEG C and a crack-sensitive area is avoided; a drawing speed of a casting machine is controlled to be 0.90min to 1.10min; the specific water flow of secondary cooling is 0.7L/kg to 0.8L/kg; the water quantity of a crystallizer is 4100L/min; the water feeding temperature of the crystallizer is 25 DEG C to 30 DEG C and the arc-alignment centering of the crystallizer is less than or equal to 100mum; the superheating temperature of tundish molten steel is 20 DEG C to 25 DEG C and has covering slag low alkalinity and high viscosity; double-water-gap and all-shield casting is adopted, and the immersion depth of water caps is 70mm to 80mm; a connecting part of the long water gap and a large ladle is sealed with argon gas after continuous casting is finished, stacking and slow cooling are carried out on the casting blank for more than or equal to 24h. By adopting the method disclosed by the invention, the surface quality problem of a weather-resisting H-shaped steel profiled continuous casting blank is solved, and the profiled continuous casting blank with qualified quality can be obtained.