The invention provides a temperature measurement device for an internal fuse wire of a capacitor. The temperature measurement device comprises an alternating current constant current source, a fiber grating sensor unit, a fiber grating signal demodulator and a monitoring host computer, wherein the fiber grating sensor unit is embedded between capacitor elements in the capacitor and reliably contacts the fuse wire in the capacitor; the fiber grating signal demodulator is connected between the fiber grating sensor unit and the monitoring host computer; and the monitoring host computer is used for receiving temperature data, output by the fiber grating signal demodulator, of a temperature measurement point of the internal fuse wire of the capacitor, and carrying out temperature alarming on the temperature measurement point of the internal fuse wire of the capacitor. Compared with the prior art, the temperature measurement device for the fuse wire in the capacitor, provided by the invention, is capable of accurately measuring the temperature of the internal fuse wire of the capacitor under the actual operation condition; a basis is provided for design and model selection of the internal fuse wire of the capacitor; the protective action reliability of the inner fuse wire is effectively improved; and the condition that internal insulation of the capacitor is not damaged by the temperature of the internal fuse wire is ensured.