  We reported the photometric calibration of Lunar-based Ultraviolet telescope
(LUT), the first robotic astronomical telescope working on the lunar surface,
for its first six months of operation on the lunar surface. Two spectral
datasets (set A and B) from near-ultraviolet (NUV) to optical band were
constructed for 44 International Ultraviolet Explorer (IUE) standards, because
of the LUT's relatively wide wavelength coverage. Set A were obtained by
extrapolating the IUE NUV spectra ($\lambda<3200\AA$) to optical band basing
upon the theoretical spectra of stellar atmosphere models. Set B were exactly
the theoretical spectra from 2000\AA\ to 8000\AA\ extracted from the same model
grid. In total, seven standards have been observed in 15 observational runs
until May 2014. The calibration results show that the photometric performance
of LUT is highly stable in its first six months of operation. The magnitude
zero points obtained from the two spectral datasets are also consistent with
each other, i.e., $\mathrm{zp=17.54\pm0.09}$mag (set A) and
$\mathrm{zp=17.52\pm0.07}$mag (set B).
