The meteorological and lightning strike data, as well as forest fire data from 1981 to 2004 are used to study the effects of climatic conditions on the occurrence of forest fires induced by lightning strikes in the forest region of Daxinganling Mountain, Inner Mongolia, and the climatic causes of the frequent lightninginduced forest fires are analyzed. The results reveal that: (1) the occurrence frequency of lightninginduced forest fires in Daxinganling had a increasing trend and occurred mostly in the period from 12 May to 16 July, 10:00 to 17:00; (2) the occurrence of lightninginduced forest fires has close relations with temperature increase, especially the increase of temperature from May to July and ground temperature; (3) the gradual decrease of precipitation and relative humidity led to greater drought damages and more lightninginduced forest fires after 1999; (4) the leading climatic cause of the frequent occurrence of lightninginduced forest fires in Daxinganling Mountain are the drier and warmer climate and frequent extreme climatic events.