The present invention discloses a dry type air core reactor temperature on-line monitor. The dry type air core reactor temperature on-line monitor is equipped with a fiber bragg grating sensor, a fiber bragg grating signal processor, a background computer and a temperature measurement work station, wherein the fiber bragg grating sensor is arranged on a reactor, is used for monitoring the temperature of a monitoring point real-timely, is not interfered by an electromagnetic field, realizes the long-distance and low-loss transmission and is the ideal selection of the reactor temperature measurement; the fiber bragg grating signal processor is connected with the other end of the fiber bragg grating sensor and is used for the optical signal transmission, the data acquisition and the subsequent processing; the background computer is communicated with the fiber bragg grating sensor via a data transmission interface, is used to calculate the optical power information, the wavelength and the like, and displays in the formats of icon, curve and report; the temperature measurement work station is connected with the background computer via a network, and monitors the temperature of the monitoring point real-timely by a man-machine exchange interface. The dry type air core reactor temperature on-line monitor of the present invention real-timely monitors the operation state of the reactor, realizes a dry type reactor temperature on-line monitoring function, and has the positive effects on the reactor and the power grid stable operation.