  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 GRB 980425 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. Our model might be able to explain the other unusual properties of
this event. 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 such as
GRB030329, GRB980329, GRB981226, and so on.
