  An MK-like spectral classification has been conducted for 1224 hot subdwarf
stars with LAMOST DR9 low-resolution spectra. The whole sample was divided into
four categories according to the spectral line characteristics: He-normal,
He-weak, He-strong C and He-strong. Each selected spectrum was assigned a
spectral class, a luminosity class and an helium class by comparing the line
depth and width with standard spectra selected in LAMOST. Relationships between
atmospheric parameters and spectral classification were also presented.
