  Applying the revised M subdwarf classification criteria discussed in Paper I
to LAMOST DR7, combining the M subdwarf sample from Savcheva et al, a new M
subdwarf sample was constructed for further study. The atmospheric parameters
for each object were derived fitting with the PHOENIX grid, combining with Gaia
DR2, the relationship between the gravity and metallicity were explored
according to the locus both in the color-absolute magnitude diagram and the
reduced proper motion diagram. Objects that have both the largest gravity and
the lowest metallicity are located away from the main-sequence cloud and may be
considered as the intrinsic M subdwarfs, which can be classified as luminosity
class VI. Another group of objects whose spectra show typical M subdwarf
characters have lower gravity and relatively moderate metal deficiency and
occupy part of the ordinary M dwarf region in both diagrams. The Galactic U , V
, W space velocity components and their dispersion show that the local Galactic
halo population sampled in the solar neighborhood is represented by objects of
high gravity and an inconspicuous bimodal metallicity distribution, with a
fraction of prograde orbits. The other M subdwarfs seem to partly belong to the
thick disk component with a significant fraction of thin disk moderately
metal-poor objects intricately mixed with them. However, the selection effects,
especially the favored anti-center direction of investigation in the LAMOST
sub-sample, but also contamination by multiplicity and parameter coupling could
play important roles and need to be further investigated.
