A theoretical analysis of plasmonic enhancement in silicon nanocone hole (NCH) solar cells with back located periodic Ag particles is presented. The nanostructured Ag back particles can significantly enhance the absorption in the near-infrared spectrum. The ultimate efficiency of the optimized nanostructure can achieve 39%, which is 22% higher than that of NCH arrays without Ag particles. The angle-dependent ultimate efficiency is also investigated. The proposed nanostructure is expected to shed some light on the design and fabrication of high-efficiency solar cells.