An ideal dispersion of graphene oxide (GO) in perfluoropolyether (PFPE) is successfully achieved via an ultrasound-assisted grafting strategy, where GO is functionalized with hexafluoropropylene oxide oligomers ((HFPO) n-COF) (denoted as UAGGH). Three types of (HFPO) n-COF-grafted GO (F nGO, n = 2, 3, 4) were efficiently prepared and their dispersion behavior in PFPE was systematically investigated. The excellent dispersibility of F nGO in PFPE arises from: (1) loss of the interlayer hydrogen bonding and the increased interlayer spacing after the fluorinated grafting; (2) the unique fluorinated-induced repulsion between F nGO layers; and (3) the exceptional compatibility between F nGO and PFPE (owing to the structural similarity of the grafted fluorinated chains to PFPE). It is these factors that effectively inhibit the spontaneous aggregation, maintain F nGO predominantly in a monolayer state within PFPE, and ultimately enhance the tribological performance of the F nGO/PFPE composite lubricant. Experimental results demonstrate that, compared with pure PFPE, the F nGO/PFPE composite reduces the friction coefficient by 16.2% and the wear volume by 56.7% for steel/steel friction pairs, and by 26.0% and 83.2%, respectively, for steel/Ti6Al4V pairs. Importantly, even after storage for over 70 days, no detectable degradation in tribological properties is observed, confirming the excellent friction-reducing and anti-wear performance of the F nGO/PFPE composite lubricant.