Abstract: A series of friction and wear tests were performed on an MG-200 high temperature and high speed test rig to investigate the effect of barite and iron ore powder doped in the drilling mud on the friction and wear behavior of a casing/drill-pipe pair. Thus the friction and wear behaviors of the casing/drill-pipe pair sliding under the lubrication of the drilling muds containing various contents of barite and iron ore powder were evaluated in a ring-on-ring configuration. The worn surface morphologies of the casing and drill-pipe were observed on a scanning electron microscope. It was found that the barite doped in the drilling mud led to the change in the wear mechanism from severe plastic flow to abrasive wear and adhesion wear. The adhesion wear increasingly become severe with increasing iron ore powder content in the drilling mud, while the barite doped in the drilling mud was beneficial to decreasing the adhesion wear and plastic deformation of the casing/drill-pipe pair. Moreover, the iron ore powder had little effect on the friction coefficient at a relatively smaller sliding speed, while a larger friction coefficient was recorded at a larger sliding speed.