  In this paper, we employ a continuous Ginzburg-Landau model to study the
behaviors of the parallel upper critical field of an intrinsically-layered
superconductor. Near $T_c$ where the order parameter is nearly homogeneous, the
parallel upper critical field is found to vary as $(1-T/T_c)^{1/2}$. With a
well-localized order parameter, the same field temperature dependence holds
over the whole temperature range. The profile of the order parameter at the
parallel upper critical field may be of a Gaussian type, which is consistent
with the usual linear Ginzburg-Landau theory. In addition, the influences of
the unit cell dimension and the average effective masses on the parallel upper
critical field and the associated order parameter are also addressed.

Superconductivity