The rare top decay $t\to cg$ in topcolor assisted technicolor models

In the framework of topcolor-assisted technicolor(TC2) models, we calculate the contributions of flavor changing scalar couplings involved the neutral top-pion ${\pi }_t^0$ and top-Higgs $h_t^0$ to the branching ratio $B_r(t⟶cg)$. We find that the value of $B_{r}(t\longrightarrow cg)$canreach$ 1\times10^{-3}$ with reasonable values of the parameters in TC2 models, which may be testable in the future experiments.