Perovskite/silicon tandem solar cells, by combining perovskite as a top absorber material and crystalline silicon as a bottom absorber material, can expand and enhance the utilization of solar spectrum. Therefore, such a tandem structure shows great potential to break through the Shockley-Queisser (SQ) limit of 31%－33% for single-junction (SJ) solar cells and is considered as one of the most promising approaches to achieving the higher performance in photoelectric conversion of solar cells. Reducing the optical losses from the surface and interfaces of cell device and making more photons propagate into the active layers are the key factors for achieving the goal. In this paper, the enhancement of spectral response and energy conversion efficiency of perovskite/silicon tandem solar cells depending on Au, Ag, Cu, Al nanosphere are studied by using the finite difference time domain method and rigorous coupled-wave analysis. The results show that owing to the introduction of metal nanosphere, the transmittance of photons propagating into the active material is promoted significantly. Therefore, the cell device achieves an apparent increase both in total absorbance and in quantum efficiency. The observed weighted average transmittance and energy conversion efficiency are increased from 73.16% and 23.09% to 79.15% and 24.97%, respectively, with an 8.14% improvement for the perovskite/silicon tandem solar cells coated with the optimized Al nanospheres.