  We construct various boundary states in the coset conformal field theory G/H.
The G/H theory admits the twisted boundary condition if the G theory has an
outer automorphism of the horizontal subalgebra that induces an automorphism of
the H theory. By introducing the notion of the brane identification and the
brane selection rule, we show that the twisted boundary states of the G/H
theory can be constructed from those of the G and the H theories. We apply our
construction to the su(n) diagonal cosets and the su(2)/u(1) parafermion theory
to obtain the twisted boundary states of these theories.
