  We investigate observational constraints on the Dvali, Gabadadze and Porrati
(DGP) model with Gamma-ray bursts (GRBs) at high redshift obtained directly
from the Union2 Type Ia supernovae data (SNe Ia) set. With the
cosmology-independent GRBs, the Union2 set, as well as the cosmic microwave
background (CMB) observations from the WMAP7 result, the baryon acoustic
oscillation, the baryon mass fraction in clusters and the observed $H(z)$ data,
we obtain that the best-fit values of the DGP model are ${\Omega_{M0},
\Omega_{rc}} =\{0.235_{-0.014}^{+0.015},0.138_{-0.048}^{+0.051}\}$, which favor
a flat universe; and the transition redshift of the DGP model is
$z_T=0.67_{-0.04}^{+0.03}$. These results lead to more stringent constraints
than the previous results for the DGP model.
