We synthesized AgCl/Au/Ag composite nanocubes (AgCl/Au/AgNCs) which consist of the core-AgCl nanocube (AgClNC) surrounded by ‘in-panel‘ Au nanoparticles and continuous Ag matrix. In comparison to the polyol synthesis, the aqueous synthesis of AgClNCs using HAuCl4, AgNO3, and polyvinylpyrrolidone is advantageous because it is fast and reliable. As-synthesized AgClNCs were combined with ascorbic acid to co-reduce the remaining AuCl4-, Ag+ and AgClNCs. After the co-reduction, NH4OH was used to confirm the reduced nanostructures by eliminating the AgClNCs that still existed in the AgCl/Au/AgNCs. Consequently, we obtained hollow nanoboxes whose panels are composed of discontinuous Au nanoparticles in continuous Ag mesh matrix (Au#AgNBs). In order to investigate the chemical components of the three nanostructures, X-ray powder diffraction (XRD) patterns were obtained for the AgClNCs, the AgCl/Au/AgNCs, and the Au#AgNBs, which clearly showed the formation of AgClNCs, the reduction of metallic precursors to form the AgCl/Au/AgNCs, and the removal of AgClNCs to leave only the Au#AgNBs. The distribution of Au and Ag in the panel of the AgCl/Au/AgNC was analyzed after the elimination of the AgClNCs by energy-dispersive X-ray spectroscopy (EDX). Importantly, the EDX results demonstrated that the panels of the AgCl/Au/AgNCs were not atomically alloyed structures, but composed of small Au nanoparticles and Ag mesh matrix. In addition, we investigated the catalytic properties of the AgClNCs, the AgCl/Au/AgNCs and the Au#AgNBs for the oxidation of o-phenylenediamine (OPD) to 2,3-diaminophenazine (DPA). The AgCl/Au/AgNCs exhibited the highest catalytic activity than AgClNCs and Au#AgNBs demonstrating the importance of the co-existence of Au, Ag and AgCl for the catalytic properties.