  We study the QCD vacuum orientation angles in correlation with the strong CP
phases. A vacuum alignment equation of the dynamical chiral symmetry breaking
is derived based on the anomalous Ward identity. It is emphasized that a chiral
rotation of the quark field causes a change of the vacuum orientation and a
change in the definition of the light pseudoscalar generators. As an
illustration of the idea, $\h\rightarrow 2\p$ decays are carefully studied in
different chiral frames. Contrary to the claim in Ref.[7], the $\theta$-term
does not directly contribute to the CP-violating processes.
