  We derive several relations between CP violating rate differences
$\Delta(B\to PV) = \Gamma(B\to PV) - \Gamma(\bar B \to \bar P \bar V)$ for
charmless $B\to P V$ decays in the Standard Model using SU(3) flavor symmetry.
It is found that although the relations between branching ratios of $\Delta S =
0$ and $\Delta S = -1$ processes are complicated, there are simple relations
independent of hadronic models between some of the $\Delta S =0$ and $\Delta S
= -1$ rate differences due to the unitarity property of the Kobayashi-Maskawa
matrix, such as $ \Delta(B\to \pi^+ \rho^-) = -\Delta(B\to \pi^+ K^{*-})$,
$\Delta(B\to \pi^- \rho^+) = - \Delta(K^- \rho^+)$. SU(3) breaking effects are
also estimated using factorization approximation. These relations can be tested
at B factories in the near future.
