  We study the superconducting transition temperature $T_c$ of the bilayer d-p
model with $d_{x^2-y^2}$-wavelike attractive interaction based on the formalism
first employed by Nozi\`{e}res and Schmitt-Rink. In the strong coupling regime,
$T_c$ obtained through this formalism are much suppressed, compared with those
through Thouless criterion only. We also find that, whether the interlayer
coupling exsists or not, $T_c$ is almost propotional to the Fermi energy in the
strong coupling regime. Thus, we can reproduce the essential nature in the
underdoped region.
