Magnetic fluid is a kind of functional material,which has both the fluidity of liquid and the magnetism of solid magnetic materials.Its application in sealing is one of the most successful applications.As a new sealing technology,magnetic fluid seals are widely used in military,chemical,aerospace and other fields.At present,the research of magnetic fluid sealing technology in sealing gas medium and vacuum has become mature.In contrast,the sealing of liquid medium has great limitations.The research progress of magnetic fluid rotary seal technology was described from three aspects:the interface stability of magnetic fluid and the liquid medium to be sealed,the process of interface destruction,and the structural design of the sealing device used for liquid medium.The technical characteristics and disadvantages of three kinds of magnetic fluid sealing structure design methods for liquid were summarized,and the prospect of magnetic fluid in sealing liquid medium was prospected.