The absorption properties of the random Al/CdS nanoshell systems are simulated using the finite difference time domain (FDTD) method. The interactions between the nanoshells have been taken into account in the simulation. By comparing the optical absorption of dispersion system with that of single nanoshell, it reveals that the inter-particle coupling cannot be neglected in the simulation of dispersion system. The absorption enhancement is affected by both the inter-particle coupling and the localized surface plasmon resonance (LSPR) effect. The dispersed nanoparticles induce longer optical path inside the dispersion system and enhance light trapping as well as absorption. It can be considered to increase the nanoshell concentration and reduce the particle size to obtain an enhanced absorption. (C) 2013 Elsevier Ltd. All rights reserved.