Lubricant on magnetic hard disk is essential to the stable lubrication at the head/diskinterface of the computer hard disk drive, The depletion phenomenon of the perfluoropolyalkylether(PFPE) lubricant ZDOL caused by the head was investigated. FC722, a type ofpoly(fiuoroalkylmethacrylate) used as anti-wetting-agent (AWA) on the magnetic head, and its ef-fect on reducing lubricant depletion was study. Time-of-flight secondary ion mass spectrometer(TOF-SIMS) was used to characterize the lubricant ZDOL and AWA. TOF-SIMS results suggestthat the lubricant depletion should be due to dynamic friction between the magnetic head and diskduring the head flying or seeking over the disk surface, the amount of lubricant picked up by thehead varying with the different flying height. The AWA coating layer on head obviously reduces theamount of lubricant picked-up. The possible molecular interaction mechanics of AWA and ZDOLwith DLC overcoat of the head was discussed. Lubricant on magnetic hard disk is essential to the stable lubrication at the head / diskinterface of the computer hard disk drive, The depletion phenomenon of the perfluoropolyalkylether (PFPE) lubricant ZDOL caused by the head was investigated. FC722, a type of poly (fiuoroalkylmethacrylate) used time-of-flight secondary ion mass spectrometer (TOF-SIMS) was used to characterize the lubricant ZDOL and AWA. TOF-SIMS results suggest that the lubricant depletion should be due to dynamic friction between the magnetic head and diskduring the head flying or seeking over the disk surface, the amount of lubricant varying up the the head varying with the different flying height. head obviously reduces theamount of lubricant picked-up. The possible molecular interaction mechanics of AWA and ZDOL with DLC overcoat of the head was discussed.