  This work presents the initial results of the drift-scan observation for the
neutral hydrogen (HI) intensity mapping survey with the Five-hundred-meter
Aperture Spherical radio Telescope (FAST). The data analyzed in this work were
collected in night observations from 2019 through 2021. The primary findings
are based on 28 hours of drift-scan observation carried out over seven nights
in 2021, which covers $60\,{\rm deg}^2$ sky area. Our main findings are: (i)
Our calibration strategy can successfully correct both the temporal and
bandpass gain variation over the $4$-hour drift-scan observation. (ii) The
continuum maps of the surveyed region are made with frequency resolution of
$28$ kHz and pixel area of $2.95\,{\rm arcmin}^2$. The pixel noise levels of
the continuum maps are slightly higher than the forecast assuming $T_{\rm
sys}=20\,{\rm K}$, which are $36.0$ mK (for 10.0 s integration time) at the
$1050$--$1150$ MHz band, and $25.9$ mK (for 16.7 s integration time) at the
$1323$--$1450$ MHz band, respectively. (iii) The flux-weighted differential
number count is consistent with the NRAO-VLA Sky Survey (NVSS) catalog down to
the confusion limit $\sim7\,{\rm mJy}/{\rm beam}^{-1}$. (iv) The continuum flux
measurements of the sources are consistent with that found in the literature.
The difference in the flux measurement of $81$ isolated NVSS sources is about
$6.3\%$. Our research offers a systematic analysis for the FAST HI intensity
mapping drift-scan survey and serves as a helpful resource for further
cosmology and associated galaxies sciences with the FAST drift-scan survey.
