A structure for improving performance of an active headrest comprises a lumbar support plate which is installed within a seat back frame and supports the body of an occupant; a lumbar support interlocking wire which operates by being interlocked with the lumbar support plate and a link bracket which is disposed on the lumbar support interlocking wire and is rotated by the lumbar support interlocking wire so as to rotate a link connecting pipe which raises an active headrest pipe; a stopper which is disposed behind the active headrest pipe and is installed to an inner side of the seat back frame; and a hooking projection which supports a lower end portion of the active headrest pipe such that the active headrest pipe cannot go down during a vehicle impact.