  We suggest that the forward-backward asymmetry $(A_{FB})$ of the charged
lepton in $gg\to H\to\gamma Z\to\gamma \ell^-\ell^+$ process could be used to
probe the CP violating $H\gamma Z$ coupling when the interference from
$gg\to\gamma Z\to\gamma \ell^-\ell^+$ process is included. With CP violation in
$H\gamma Z$ coupling, the interference effect leads to a non-vanishing
$A_{FB}$, which is also sensitive to the strong phase differences. The resonant
and non-resonant strong phases together make $A_{FB}(\hat{s})$ change sign
around Higgs mass $M_H$. For phenomenology study, we suggest the integral over
one-side mass region below $M_H$ to magnify the $A_{FB}$ strength.
