Platinum diselenide (PtSe₂) is regarded as a core candidate material for high-performance microelectronic devices in the post-Moore era due to its tunable bandgap, high carrier mobility, and environmental stability. However, the complex surface dynamic processes of PtSe₂, particularly the non-volatility of Pt-based oxidation/halogenation products, poses a significant challenge. Achieving high-resolution patterning that is simultaneously residue-free and causes low interface damage remains a critical bottleneck restricting high-density integration. In this study, combining experimental characterization with Density Functional Theory (DFT) calculations, we report an innovative Oxidation-Mediated Physical Sputtering (OMPS) strategy. This strategy overcomes the dependence of traditional Atomic Layer Etching (ALE) on product volatility by decoupling the processes of lattice oxidation reconstruction and physical sputtering removal. Specifically, we modulate surface bonding characteristics via oxidation to induce lattice softening, thereby in-situ reconstructing the chemically inert PtSe₂ lattice structure into a structurally metastable sacrificial oxide layer. Subsequently, low-energy Ar ion sputtering is applied to achieve low-damage, highly selective physical removal. Based on OMPS, we achieved high-resolution nanopatterning of PtSe₂ with a minimum linewidth of approximately 20 nm, featuring atomically clean interfaces and excellent compatibility with photoresists. The proposed innovative strategy offers a viable solution to the long-standing hurdle of non-volatile etching byproducts and lays a solid process foundation for the scalable and high-density integration of PtSe₂ and other two-dimensional materials.