Surface patterns of nanoshell arrays play an important role in diverse applications including surface-enhanced Raman scattering (SERS) sensors, lithium-ion batteries, solar cells, and optical devices. This paper describes an innovative surface nanopatterning technique for realizing large-scale ordered arrays of metallic spherical nanoshells with well-defined structures. Ag nanoshell arrays are prepared using polystyrene sphere templates by an electrophoretic process in Ag colloidal solutions. The fabricated Ag nanoshell arrays have a high controllability of the structural parameters, including the diameter, the surface roughness, and the intershell spacing, giving rise to the tunable properties of nanoshell arrays. As an example, tunable SERS and localized surface plasmon resonance of the nanoshell arrays are demonstrated by controlling the structural parameters. The surface nanopatterning technique shown in this paper is a general fabrication process in achieving not only metallic nanoshell arrays, but also nanoshell arrays of semiconductors and metallic oxides.