  In this paper, forward-backward asymmetry and differential cross section of
top quark in flavor violating $Z'$ model up to $\mathscr{O}(\alpha_s^2
\alpha_X)$ at Tevatron are calculated. In order to account for the top observed
large forward-backward asymmetry, the new coupling $g_X$ among $Z'$ and quarks
will be not much less than strong coupling constant $g_s$. After including the
new higher order correction, the differential cross section can fit the data
better than those only including the leading contributions from $Z'$, while the
forward-backward asymmetry is still in agreement with the measurement.
