  We study the system that two atoms simultaneously interact with a single-mode
thermal field via different couplings and different spontaneous emission rates
when two-photon process is involved. It is found that we indeed can employ the
different couplings to produce the atom-atom thermal entanglement in two-photon
process. The different atomic spontaneous emission rates are also utilizable in
generating thermal entanglement. We also investigate the effect of the cavity
leakage. To the initial atomic state $|ee> ,$a slight leakage can relieve the
restriction of interaction time and we can obtain a large and steady
entanglement.
