Platinum- group elements (PGE) mineralization is mainly hosted in magmatic sulfide deposits associated with mafic- ultramafic magmas. The mechanism of PGE enrichment in magmatic systems is an important issue of the genesis of magmatic sulfide deposits. In classical theory, the high PGE tenors in the sulfides are attributed to the extremely high sulfide- silicate partition coefficient (105~106) and the mass of silicate melt with which a given mass of sulfide melt has been equilibrated (R- factor). However, this conventional model has been challenged by recent experimental and empirical results of PGE occurrences in micro- to nano- scale. Here, we briefly introduce some case studies showing that PGE nanoparticles can be physically trapped in sulfide and/or chromite and then form PGE nanoalloy by oriented attachment and flocculation of many coexisting nanoparticles. On the other hand, PGE (e.g., Pt and Pd) incline to combine with semimetal elements (TABS: Te, As, Bi, Sb and Sn) and Se, forming PGE- rich arsenides, bismuthides, tellurides or stannides. Therefore, besides thermodynamically partitioning of PGE between sulfide and silicate melts, the assemblage and coalescence of PGE nanoparticles and the existence of TABS may play important roles in the collection of PGE in sulfides. As platinum- group minerals are commonly micrometer/nanometer- sized, the detailed investigation of PGE occurrences in variable mineral phases using advanced micro- scale analytical techniques such as FIB, HRTEM, nano- SIMS and APT will help for a better understanding of the PGE enrichment mechanism, and may provide some new insights for the metallogenic theory of magmatic sulfide deposits.