  We study the zero temperature quantum dynamical critical behavior of the
anisotropic XY chain under a sudden quench in a transverse field. We
demonstrate theoretically that both quench magnetic susceptibility and
two-particle quench correlation can be used to describe the dynamical quantum
phase transition (QPT) properties. Either the quench magnetic susceptibility or
the derivative of correlation functions as a function of initial magnetic field
$a$ exhibits a divergence at the critical points when final magnetic field $b$
is fixed. A special case that final magnetic field $b$ is just at the critical
point is discussed separately. Some of the critical exponents of the dynamical
QPT are obtained and the long-range correlation of the quench system is
analyzed. We also compare our result with that of the static QPT.
