Dissipative particle dynamics (DPD) was employed to simulate the diffusion of rigid rodlike polymers in isotropic solutions. In a dilute solution range, the simulated diffusion behavior is in good agreement with that as described by the Kirkwood theory. In a semi-dilute range, the simulation shows that the DPD model adopting soft repulsive interactions can effectively reproduce the entanglement effect on both rotational and translational diffusions. The rotational diffusion coefficient D-r obeys the asymptotic scaling law D-r similar to (vL(3))(-2) (v is the number of polymers per volume and L is the polymer length) for the large vL(3), which corresponds to formation of a completely enclosed tube in the Doi-Edwards theory. The parallel translational diffusion coefficient D parallel to decreases with v increase, which can be attributed to the friction effect of surrounding medium. The perpendicular translational diffusion coefficient D-perpendicular to. decays more drastically with v increase, which is caused by the topological constraint. (C) 2013 Elsevier Ltd. All rights reserved.