  We perform a discrimination procedure with the spectral index diagram of TiO5
and CaH2+CaH3 to separate M giants from M dwarfs. Using the M giant spectra
identified from the LAMOST DR1 with high signal-to-noise ratio (SNR), we have
successfully assembled a set of M giant templates, which show more reliable
spectral features. Combining with the M dwarf/subdwarf templates in Zhong et
al. (2015), we present an extended M-type templates library which includes not
only M dwarfs with well-defined temperature and metallicity grid but also M
giants with subtype from M0 to M6. Then, the template-fit algorithm were used
to automatically identify and classify M giant stars from the LAMOST DR1. The
result of M giant stars catalog is cross-matched with 2MASS JHKs and WISE W1/W2
infrared photometry. In addition, we calculated the heliocentric radial
velocity of all M giant stars by using the cross-correlation method with the
template spectrum in a zero-velocity restframe. Using the relationship between
the absolute infrared magnitude MJ and our classified spectroscopic subtype, we
derived the spectroscopic distance of M giants with uncertainties of about 40%.
A catalog of 8639 M giants is provided. As an additional search result, we also
present 101690 M dwarfs/subdwarfs catalog which were classified by our
classification pipeline.
