  Inspired by the diphoton signal excess observed in the latest data of 13 TeV
LHC, we consider either a 750 GeV real scalar or pseudo-scalar responsible for
this anomaly. We propose a concrete vector-like quark model, in which the
vector-like fermion pairs directly couple to this scalar via Yukawa
interaction. For this setting the scalar is mainly produced via gluon fusion,
then decays at the one-loop level to SM diboson channels $gg, \gamma\gamma, ZZ,
WW$. We show that for the vector-like fermion pairs with exotic electric
charges, such model can account for the diphoton excess and is consistent with
the data of 8 TeV LHC simultaneously in the context of perturbative analysis.
