Ground fire is an igniting phenomenon that is difficult to control and lightning is the main cause of ground fire. The mechanism of lightning-ground fire is very complex. Daxing’anling Mountains forest region is the place that lighting-groundfire occurs more often and regularly. Our study on lightning-groundfire of this zone in 2002 shows: much more soil near the surface and the ground fuel is the matter preconditions of lightning-groundfire, and the weather conditions hasten the occurrence of lightning-groundfire. Especially in the conditions with low precipitation, long time drought, increasing surface temperature, relative humidity depressing and fuel dryness, lightning-groundfire is easy to occur. Lightning-groundfire has spatiotemporal character. Lightning-groundfire occurs mostly in primary forest zone, such as conifer forest, broadleaf forest, conifer and broadleaf mixed forest. Lightning-groundfire often burns slowly, for a long time and completely, and it has the characteristics of high conceal Ground fire is an igniting phenomenon that is difficult to control and lightning is the main cause of ground fire. The mechanism of lightning-ground fire is very complex. Daxing’anling Mountains forest region is the place that lighting-groundfire occurs more often and regularly Our study on lightning-groundfire of this zone in 2002 shows: much more soil near the surface and the ground fuel is the matter preconditions of lightning-groundfire, and the weather conditions hasten the occurrence of lightning-groundfire. Especially in the conditions with low precipitation, long time drought, increasing surface temperature, relative humidity depressing and fuel dryness, lightning-groundfire is easy to occur. Lightning-groundfire has spatiotemporal character. Lightning-groundfire due mostly in primary forest zone, such as as conifer forest, broadleaf forest , brightifer-groundfire often burns slowly, for a long time and completely, and it has the characteristi cs of high conceal