Herein we reported a green synthetic route for the preparation of Au–Pt core–shell nanoparticle chains in a two-step route without the use of any surfactants. In the synthesis, compressed hydrogen was used as a reducing reagent, which also promoted the assembly of particle chains. The as-prepared monodispersed gold nanoparticles were manipulated by dipoles to form chain-like nanostructures under high pressure; meanwhile, in situ epitaxial growth of Pt shell on gold nanochains occurred, leading to the formation of Au–Pt core–shell nanoparticle chains. The resulting bimetallic Au–Pt core–shell chains showed excellent catalytic activity as cathodes in lithium oxygen batteries with a low charge–discharge over potential and outstanding cycle performance because of its clean catalytic surface, interconnected nanostructure, which provided a good electron path and innate synergistic effect.