We analyze a catalog comprising 781,232 spectra from 641,095 M dwarf stars from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) low-resolution spectroscopic data release 9. Based on the equivalent width of the H{alpha} line, we ascertain the activity properties of the stars, identifying a total of 107,134 active stars, with 31175 exhibiting H{alpha} variations. Furthermore, we establish a positive correlation between starspot activity from Transiting Exoplanet Survey Satellite light curves, and chromospheric activity observed through LAMOST spectra on M dwarf stars. Utilizing LAMOST and Gaia data, we map the two-dimensional distribution of active fractions across all M dwarfs in the Milky Way based on H{alpha} and H{beta} lines, confirming a decrease in the active fraction as the distance above the Galactic disk increases. Additionally, we investigate the relationship between chromospheric activity and absolute height above the Galactic disk in various M subtypes. Our findings reveal distinct trends: for M0 to M5 dwarf stars, the active fraction of H{alpha} and H{beta} lines rapidly decreases within the 0-300pc range. In the 300-500pc range, M0 to M4 dwarf stars exhibit a gradual increase, followed by a decrease in the 500-1000 pc range. Conversely, M5 dwarf stars show no significant gradual increase in the 300-500pc range and decrease in the 500-1000pc range. More data will be needed to confirm the phenomenon.

Cone search capability for table J/ApJS/274/36/mdwarfs (Stellar parameters of M dwarf stars from LAMOST DR9 spectra (Table 1) and calculation parameters (Table 2))