Plasmas generated in contact with liquids have attracted considerable attention as a novel reactive field in nano-biomaterial creation because the brand-new chemical and biological reactions are yielded at the gas–liquid interface, which are induced by the physical actions of the non-equilibrium plasmas. Highly ordered periodic structures of gold nanoparticles (AuNPs) are formed by transcribing the plasma structure to the surface of the liquid, where the spatially selective synthesis of the AuNPs is realized. Furthermore, the plasma structure is controlled using a ring or disk electrode under strong magnetic fields up to 4 T. The ring structure of the nanoparticles is found to be formed in accordance with the shadow region of the ring electrode. It is found that the AuNPs are synthesized by the reduction effect of the hydrogen radical via irradiation of neutral radicals of the plasma and are destroyed by the oxidation effect of the fluorine radical via high-energy plasma-ion irradiation.