We study the critical temperature,
free energy, entropy, and trace anomaly of the gluon plasma using the T=0
dilaton potential in the gravity theory of AdS/QCD. The finite temperature
observables are calculated in two ways; once
from the Page-Hawking computation of the free energy, and secondly using the
Beckenstein-Hawking equality of the entropy with the area of the horizon.
Renormalization is well defined, because the T=0 theory has
asymptotic freedom. We further investigate the change of the critical temperature
with the number of flavours induced by the change of the running coupling constant.
The finite temperature behaviour of the Polyakov loop, heavy quark-antiquark free energy
and spatial string tension follow from the corresponding string theory in AdS5.
Comparison with lattice simulations is made.