The invention relates to a novel built-in airbag type safety helmet which mainly comprises a lightweight thin-walled helmet body (9), an adjustable inner ring (11), a fixed rope (12), a fixed rope switch (13), an adjustable inner ring control switch (14) and an airbag (15). The adjustable inner ring control switch (14) is used for adjusting the tightness; the safety helmet is fixed on a human head through the fixed rope switch (13) to prevent falling-off; the lightweight thin-walled helmet body (9) provides penetration resistance, lateral rigidity, electrical insulation and flame retardance required by the safety helmet; the airbag (15) plays a buffering role and absorbs the impact force; when underground fire, flood, explosion and other accidents occur, the airbag (15) can also act as a temporary self-rescuer, so that miners have longer time to reach a safety zone.