  In the frameworks of the littlest Higgs($LH$) model and its extension with
T-parity($LHT$), we studied the associated $t\bar th^0$ production process $e^+
e^- \to \gamma\gamma \to t \bar t h^0$ at the future $e^+e^-$ linear colliders
up to QCD next-to-leading order. We present the regions of $\sqrt{s}-f$
parameter space in which the $LH$ and $LHT$ effects can and cannot be
discovered with the criteria assumed in this paper. The production rates of
process $\gamma\gamma \to t \bar t h^0$ in different photon polarization
collision modes are also discussed. We conclude that one could observe the
effects contributed by the $LH$ or $LHT$ model on the cross section for the
process $e^+ e^- \to \gamma\gamma \to t \bar t h^0$ in a reasonable parameter
space, or might put more stringent constraints on the $LH$/$LHT$ parameters in
the future experiments at linear colliders.
