  In this paper we first obtain Friedmann equations for the $(n-1)$-dimensional
brane embedded in the $(n+1)$-dimensional bulk, with intrinsic curvature term
of the brane included in the action (DGP model). Then, we show that one can
always rewrite the Friedmann equations in the form of the first law of
thermodynamics, $dE=TdS+WdV$, at apparent horizon on the brane, regardless of
whether there is the intrinsic curvature term on the brane or a cosmological
constant in the bulk. Using the first law, we extract the entropy expression of
the apparent horizon on the brane. We also show that in the case without the
intrinsic curvature term, the entropy expressions are the same by using the
apparent horizon on the brane and by using the bulk geometry. When the
intrinsic curvature appears, the entropy of apparent horizon on the brane has
two parts, one part follows the $n$-dimensional area formula on the brane, and
the other part is the same as the entropy in the case without the intrinsic
curvature term. As an interesting result, in the warped DGP model, the entropy
expression in the bulk and on the brane are not the same. This is reasonable,
since in this model gravity on the brane has two parts, one induced from the
$(n+1)$-dimensional bulk gravity and the other due to the intrinsic curvature
term on the brane.
