  We present extensive ultraviolet, optical, and near-infrared observations of
the type IIP supernova (SN IIP) 2013ej in the nearby spiral galaxy M74. The
multicolor light curves, spanning from $\sim$ 8--185 days after explosion, show
that it has a higher peak luminosity (i.e., M$_{V}$ $\sim$$-$17.83 mag at
maximum light), a faster post-peak decline, and a shorter plateau phase (i.e.,
$\sim$ 50 days) compared to the normal type IIP SN 1999em. The mass of
$^{56}$Ni is estimated as 0.02$\pm$0.01 M$_{\odot}$ from the radioactive tail
of the bolometric light curve. The spectral evolution of SN 2013ej is similar
to that of SN 2004et and SN 2007od, but shows a larger expansion velocity
(i.e., $v_{Fe II} \sim$ 4600 km s$^{-1}$ at t $\sim$ 50 days) and broader line
profiles. In the nebular phase, the emission of H$\alpha$ line displays a
double-peak structure, perhaps due to the asymmetric distribution of $^{56}$Ni
produced in the explosion. With the constraints from the main observables such
as bolometric light curve, expansion velocity and photospheric temperature of
SN 2013ej, we performed hydrodynamical simulations of the explosion parameters,
yielding the total explosion energy as $\sim$0.7$\times$ 10$^{51}$ erg, the
radius of the progenitor as $\sim$600 R$_{\odot}$, and the ejected mass as
$\sim$10.6 M$_{\odot}$. These results suggest that SN 2013ej likely arose from
a red supergiant with a mass of 12--13 M$_{\odot}$ immediately before the
explosion.
