  We present that the model of inverse Compton scattering of cosmic microwave
background photons (IC/CMB) could well explain the large-scale jet X-ray
radiation of 3C 273, and does not violate new Fermi observations. For the
individual knots, the synchrotron spectrum of the low-energy electrons
responsible for the IC/CMB X-ray emission may be different from the
extrapolation of the 10GHz radio spectrum of knots. Based on the IC/CMB model
for the 3C 273 large-scale jet, the Fermi observations may mainly come from the
small-scale jet of 3C 273 (i.e., the core). Future observations could examine
our interpretation on the spectral energy distributions (SED) of knots and
large-scale jet in 3C 273.
