  Using a simple off-axis jet model of GRBs, we can reproduce the observed
unusual properties of the prompt emission of GRB980425, such as the extremely
low isotropic equivalent gamma-ray energy, the low peak energy, the high
fluence ratio, and the long spectral lag when the jet with the standard energy
of ~10^{51}ergs and the opening half-angle of \Delta\theta=~10-30 degree is
seen from the off-axis viewing angle ~\Delta\theta+10/\gamma, where \gamma is a
Lorentz factor of the jet. For our adopted fiducial parameters, if the jet that
caused GRB980425 is viewed from the on-axis direction, the intrinsic peak
energy Ep(1+z) is ~2.0-4.0 MeV, which corresponds to those of GRB990123 and
GRB021004. We also discuss the connection of GRB980425 in our model with the
X-ray flash, and the origin of a class of GRBs with small E_gamma.
