The surface plasmon resonance-enhanced optical absorption in thin silicon solar cells through hemispherical silver nanoparticles (NPs) was investigated in this work. The effect of particle size, the distance between particles, spacing layer, and thickness of silicon substrate on absorption enhancement is studied using a finite-difference time-domain (FDTD) technique. The results showed that an enhancement of 25% in absorption could be achieved by integrating the silver particles on 500-nm semi-infinite thick silicon solar cells with the proper combination of NP parameters compared to those without silver particles. In addition, absorption enhancement can be further modified by the spacing of the oxide layer and thickness of silicon substrate as seen in our calculations. The calculated results shown in this paper will serve as a valuable reference for further theoretical and experimental studies.