We investigate the self-assembly of hard rod-shaped particles with an affinity for A block in diblock AB copolymer templates. The results are consistent with a series of recent experimental findings. Furthermore, we construct the phase diagrams of the mixture with different aspect ratios of particles by changing the particle concentration phi(p) and the volume fraction f of the A block. The variation of the aspect ratio in different particle concentrations will significantly influence the effective volume of the A component and consequent phase behavior of nanoparticle/copolymer hybrid systems, which may account for the emergence of some unexpected phenomena of morphological transitions. The present study provides insightful guidance to control the nanometer-length-scale structures of shaped particles for potential applications as functional devices.