The present disclosure discloses a vacuum degree detection device, a monitoring system and a vacuum arc-extinguishing chamber thereof, wherein, in the vacuum degree detection device, a ceramic insulating housing is sealingly fixed to an end face cover plate of the vacuum arc-extinguishing chamber, the ceramic insulating housing is a circular ring-shaped structure coaxial with a conductive rod on the end face cover plate, a sealing area formed by the end face cover plate and the ceramic insulating housing is provided with a through hole communicating with the vacuum arc-extinguishing chamber; a thermoelectric vacuum sensor is disposed inside the ceramic insulating housing to detect the vacuum degree of the vacuum arc-extinguishing chamber, a cold end is fixed to the end face cover plate, an electrode is supported on the cold end, a thermoelectric arm is supported on the electrode, a hot end is laminated to the thermoelectric arm.