The invention discloses a pouring protecting device and a pouring protecting control method for a continuously cast ladle and belongs to the technical field of pouring equipment and methods for continuously cast ladles. The pouring protecting device and the pouring protecting control method are used for improving pouring sealing protecting effect of a molten steel outlet of the ladle. The technical scheme includes that a horizontal annular groove forms on the upper portion of the inner cavity surface of a long molten steel port at the joint of the long molten steel port and the molten steel outlet and is connected with an argon introducing pipe, the argon introducing pipe is connected with an argon supply pipe, and an automatic adjusting valve and a PID (Proportion Integration Differentiation) controller are installed in the argon supply pipeline. According to the sealed portion, for protecting argon demand, the automatic argon adjusting valve is used to automatically compensate argon supply as constant pressure, and an alarm can be provided so as to take emergency measures when sealing failure occurs. The pouring protecting device is convenient to construct and good in sealing effect and is capable of sealing the joint of the molten steel outlet and the long molten steel port so as to prevent the air from entering the molten steel, eliminate secondary pollution of the molten steel and guarantee quality of the molten steel. Meanwhile, argon consumption is reduced, and the pouring protecting device has remarkable economic benefits.