The deposition-deoxidization behavior of de-oxidizer in middle frequency furnace was expounded.It was found that the deoxidization ability is deteriorated with the increase of oxidization degree of the element when some elements reach to a certain in the furnace.The excessive addition of metal oxide element can improve deoxidization ability and reduce the oxygen content in molten steel to decrease non-metal inclusions

which is helpful for the purification of molten steel.