Abstract: Based on the forest lightning fire data from 1980 to 2018 in Daxing'anling, Inner Mongolia, this study uses quantile regression, Mann Kendall trend test and sliding t test to analyze the time and space scales of lightning fire. The time dynamic characteristics analyzed the fire frequency on the scale of year, fire prevention period and season, and the spatial dynamic characteristics studied the spatial change of fire on the scale of administrative division and altitude. The results showed that the number of lightning fires in Daxing'anling, Inner Mongolia, was less from 1980 to 1999, and showed an upward trend from 2000 to 2010. The fire rose sharply from 2000 to 2010, reached the peak in 2010, and showed a downward trend from 2011 to 2018; Spring and summer are the main seasons for forest lightning fires, and the number of lightning fires in winter is less, and the fire in the fire danger period shifts and extends to summer. The spatial distribution is characterized by a decreasing trend from the northeast to the southwest. Lightning fires occur frequently in Oroqen Autonomous Banner, Arong Banner, Erguna city and Molidawa Daur Autonomous Banner. Daxing'anling in Inner Mongolia is rich in forest resources. By studying the spatio-temporal dynamic change trend of lightning fire in a long time series, we should strengthen the fire prevention monitoring and prevention measures of forest lightning fire in spring and summer, and adjust the fire prevention resources appropriately, so as to further reduce the number of fires in Daxing'anling.