  The top-pair production in association with a $Z^0$-boson at a photon-photon
collider is an important process in probing the coupling between top-quarks and
vector boson and discovering the signature of possible new physics. We describe
the impact of the complete supersymmetric QCD(SQCD) next-to-leading order(NLO)
radiative corrections on this process at a polarized or unpolarized photon
collider, and make a comparison between the effects of the SQCD and the
standard model(SM) QCD. We investigate the dependence of the lowest-order(LO)
and QCD NLO corrected cross sections in both the SM and minimal supersymmetric
standard model(MSSM) on colliding energy $\sqrt{s}$ in different polarized
photon collision modes. The LO, SM NLO and SQCD NLO corrected distributions of
the invariant mass of $t\bar t$-pair and the transverse momenta of final
$Z^0$-boson are presented. Our numerical results show that the pure SQCD
effects in \ggttz process can be more significant in the $+ +$ polarized photon
collision mode than in other collision modes, and the relative SQCD radiative
correction in unpolarized photon collision mode varies from 32.09% to $-1.89 %$
when $\sqrt{s}$ goes up from $500 GeV$ to $1.5 TeV$.
