  In our work, we analyse $5\times10^{4}$ single pulses from the recycled
pulsar PSR J2222$-$0137 in one of its scintillation maxima observed by the
Five-hundred-meter Aperture Spherical radio Telescope (FAST). PSR J2222$-$0137
is one of the nearest and best studies of binary pulsars and a unique
laboratory for testing gravitational theories. We report single pulses' energy
distribution and polarization from the pulsar's main-pulse region. The single
pulse energy follows the log-normal distribution. We resolve a steep
polarization swing, but at the current time resolution ($64\,\mu{\rm s}$), we
find no evidence for the orthogonal jump in the main-pulse region, as has been
suspected. We find a potential sub-pulse drifting period of $P_{3} \sim
3.5\,P$. We analyse the jitter noise from different integrated numbers of
pulses and find that its $\sigma_{j}$ is $270\pm{9}\,{\rm ns}$ for 1-hr
integration at 1.25 GHz. This result is useful for optimizing future timing
campaigns with FAST or other radio telescopes.
