  In this paper, we investigate the validity of the generalized second law of
thermodynamics of the universe in the DGP brane world.The boundary of the
universe is assumed to be enclosed by the dynamical apparent horizon or the
event horizon. The universe is chosen to be homogeneous and isotropic and the
validity of the first law has been assumed here. The matter in the universe is
taken in the form of non-interacting two fluid system- one component is the
holographic dark energy model and the other component is in the form of dust.
