The invention relates to a production method for a carburizing bearing steel G20Cr2Ni4 continuous casting round billet. The method comprises the following steps that primary melting molten steel with the low carbon, the low phosphorus and the low harmful elemental content is melted in an electric-arc furnace; deoxidation, desulfuration and alloying are conducted in a ladle refining furnace, vacuum degassing is conducted in a VD furnace, and after vacuum degassing (VD), ladle hoisting and continuous casting are conducted; a big molten steel ladle is injected into a tundish through a long nozzle with argon blowing protection, the molten steel in a crystallizer is cooled in a cold region, and the molten steel is electromagnetically mixed through an external crystallizer electromagnetic mixer; the cast billet is cooled and solidified in the direction perpendicular to a steel pouring platform; the cast billet is cut into cast billet bodies with the fixed size in the perpendicular direction through a flame cutting machine synchronous with the casting speed, and the cast billet bodies are hoisted by a steel hooking machine to a billet discharging roller bed and discharged; and after the billet bodies are discharged, the cast billet bodies are put into a pit and subjected to slow cooling or direct hot-charging forging. The method for the carburizing bearing steel G20Cr2Ni4 continuous casting round billet is high in billet yield and low in production cost.