Supersymmetric electroweak corrections to t bar{t} h associated production at e+e- colliders

The electroweak corrections of order ${\cal O}(\alpha_{\rm em} m^2_{t,b}/m^2_w)$and${\cal O}(\alpha_{\rm em} m^3_{t,b}/m^3_w)$ to Higgs boson associated production with top quark pair are calculated at $e^{+}{e}^{-}$ colliders in the standard model (SM), the two-Higgs-doublet model (2HDM) and the minimal supersymmetric standard model (MSSM). These corrections are a few percent in general, and in the MSSM they can be over ten percent for favorable parameter values allowing by current precise experiments. The total cross sections including the electroweak corrections get their maximal near $\sqrt{s} = 700$GeV, and can reach 2.8 fb, 2.7 fb and 2.5 fb in the SM, the 2HDM and the MSSM, respectively.