  We consider a $SU(3)_c \times SU(3)_L \times U(1)_X$ model from a $SU(6)$
Grand Unified Theory (GUT). In order to explain the anomalous magnetic moments
of muon and electron, we introduce two new scalar triplets without vacuum
expectation values (VEVs) so that the leading contributions to $\Delta a_{\mu}$
and $\Delta a_{e}$ can avoid the suppression from small muon mass. In addition,
the Higgs potential stability of this 331 model is studied by giving a set of
sufficient conditions to ensure the boundedness from below of the potential.
