The utility model provides an one -level pressure relief device for rebreather, include the main valve body with set up on the main valve body be used for the high -pressure gas decompression the relief pressure valve, be used for to the gas filled inflation valve of the high pressurized air source of input, be used for guaranteeing that input pressure is at the relief valve of operating pressure within range, the manometer that is used for showing input gas pressure, be used for controlling the gas circuit stop valve of opening / closing, the joint of giving vent to anger, be equipped with on the main valve body main inlet channel and link to each other with main inlet channel aerify passageway, escape way, by passageway, pressure detection passageway, air outlet channel, the inflation valve is adorned in aerifing the passageway, the relief valve is adorned in escape way, the stop valve is adorned in ending the passageway, the passageway in pressure detection is adorned to the manometer, give vent to anger to connect and adorn in air outlet channel. The utility model discloses can be used to the one -level decompression and the closing control of rebreather, have advantages such as integrated level height, structure are small and exquisite, convenient to use, safe and reliable.