  3C 207 is a lobe-dominant radio galaxy with one sided jet and the bright
knots in kpc-Mpc scale were resolved in the radio, optical and X-ray bands. It
was confirmed as a gamma-ray emitter with Fermi/LAT, but it is uncertain
whether the gamma-ray emission region is the core or knots due to the low
spatial resolution of Fermi/LAT. We present an analysis of its Fermi/LAT data
in the past 9 years. Different from the radio and optical emission from the
core, it is found that the gamma-ray emission is steady without detection of
flux variation over 2 sigma confidence level. This likely implies that the
gamma-ray emission is from its knots. We collect the radio, optical, and X-ray
data of knot-A, the closest knot from the core at 1 arcsec, and compile its
spectral energy distribution (SED). Although the single-zone
synchrotron+SSC+IC/CMB model by assuming knot-A at rest can reproduce the SED
in the radio-optical-X-ray band, the predicted gamma-ray flux is lower than the
LAT observations and the derived magnetic field strength deviates the
equipartition condition with 3 orders of magnitude. Assuming that knot-A is
relativistically moving, its SED from radio to gamma-ray bands would be well
represented with the single-zone synchrotron+SSC+IC/CMB model under the
equipartition condition. These results likely suggest that the gamma-ray
emission may be from knot-A via the IC/CMB process and the knot should have
relativistical motion. The jet power derived from our model parameters is also
roughly consistent with the kinetic power estimated with the radio data.
