  The quasi-simultaneous multi-wavelength emission of TeV blazar 3C 66A is
studied by using a one-zone multi-component leptonic jet model. It is found
that the quasi-simultaneous spectral energy distribution (SED) of 3C 66A can be
well reproduced, especially its {\it Fermi}-LAT first 3 months average spectrum
can be well reproduced by the synchrotron-self Compton (SSC) component plus
external Compton (EC) component of the broad line region (BLR). Clues on its
redshift and gamma-ray emission location are obtained. The results indicate the
following. (i) On the redshift; The theoretical intrinsic TeV spectra can be
predicted by extrapolating the reproduced GeV spectra. Through comparing this
extrapolated TeV spectra with the extragalactic background light (EBL)
corrected observed TeV spectra, it is suggested that the redshift of 3C 66A
could be between 0.1 and 0.3, the most likely value is $\sim$ 0.2. (ii) On the
gamma-ray emission location; To well reproduce the GeV emission of 3C 66A under
different assumptions on BLR, the gamma-ray emission region is always required
to be beyond the inner zone of BLR. The BLR absorption effect on gamma-ray
emission confirms this point.
