Abstract: Surface subsidence induced by coal mining will generate fissures in surrounding rock which may form air-leakage passageway from surface to underground gob and result in spontaneous combustion of discarded coal in gob.In order to solve the problem of coal spontaneous combustion under full-mechanized mining condition,influence of air-leakage on coal spontaneous combustion in gob at initial stage of surface subsidence was analyzed.Comparison of air-inlet flow and air-return flow proved air-leakage from surface.Applying backfilling the fissures with surface earth effectively solved air-leakage problem.