The present invention relates to an airborne high-temperature superconducting full-tensor magnetic gradiometer loss-of-lock detection and automatic recovery method and circuit. The circuit is formed by connecting a full-tensor magnetic gradient probe with an NI measuring and controlling module through a multichannel SQUID loss-of-lock detection and automatic recovery circuit. According to the method and circuit, a problem is resolved that misjudgment is easily caused by an experimenter when judging whether loss-of-lock occurs at an SQUID magnetic sensor based on experience as the experimenterneeds to observe an output voltage signal of the SQUID magnetic sensor by naked eyes in a magnetic field measurement process, a technical solution of automatic recovery after an SQUID magnetic sensorloss-of-lock is proposed, and a problem that a reset operation after the SQUID magnetic sensor loss-of-lock is manually recovered by the experimenter is resolved. Compared with an existing full-tensormagnetic gradiometer, a method based on a signal differential entropy is proposed to detect and judge a loss-of-lock signal of the SQUID magnetic sensor, loss-of-lock detection accuracy is improved,and reset operation timeliness is enhanced to a great extent.