  BL Lacertae (BL Lac) objects at high redshifts ($z\geq 2$) are rarely
detected. Through careful analysis of the SDSS spectrum, BZB J1450+5201 is
confirmed to be a high-$z$ BL Lac object with $z\geq$ 2.471 by identifying the
Ly$\alpha$ 1216 and CIV 1548/1550 absorption lines. This indicates that BZB
J1450+5201 is the most distant BL Lac object discovered to date. Careful
analysis of the five-year \fermi data of 2FGL J1451.0+5159 shows that its
$\gamma$-ray emission is robust with confidence level of 6.2$\sigma$ at 1-3 GeV
and 6.7$\sigma$ at 3-10 GeV, and that the confusion of bright neighbor is
negligible, which can not be fixed in the analysis of the two-year data.
Meanwhile, 2FGL J1451.0+5159 is confirmed to be associated with BZB J1450+5201
using the five-year data. The analysis of multiwavelength data, from radio to
$\gamma$-ray energies, indicates BZB J1450+5201 is an intermediate synchrotron
peaked (ISP) source and consistent with distributions of other ISP sources at
lower redshifts in the second LAT AGN catalog. The pure SSC model seems to be
disfavoured, while scattering of weak external emission plus SSC process can
provide a satisfactory description of the broadband emission.
