  Polarized radio emission of RRAT J1854+0306 is investigated with single
pulses using Five-hundred-meter-Aperture Spherical Telescope. Its emission is
characterized by nulls, narrow and weak pulses, and occasional wide and intense
bursts with a nulling fraction of 53.2%. Its burst emission is typically of one
rotation, and occasionally of two or three or even five rotations at the most,
but without significant periodicity. The integrated pulse profile has an
'S'-shaped position angle curve that is superposed with orthogonal modes, from
which geometry parameters are obtained. Individual pulses exhibit diverse
profile morphology with single, double, or multiple peaks. The intensity and
width of these pulses are highly correlated, and bright pulses generally have
wide profiles with multiple peaks. These nulling behaviours, profile
morphology, and polarization demonstrate that a rotating radio transient has
the same physical origins as the normal pulsars.
