The utility model provides a fuse temperature measurement apparatus in a capacitor. The fuse temperature measurement apparatus in the capacitor comprises an alternating current constant current source, a fiber grating sensor unit and a fiber grating signal demodulation instrument. The fiber grating sensor unit is embedded in the capacitor. The fiber grating signal demodulation instrument is connected to the fiber grating sensor unit through a fiber. Compared with fuse temperature measurement apparatuses in the prior art, the fuse temperature measurement apparatus in the capacitor provided by the utility model can accurately measure the temperature of fuses in the capacitor in a practical operation condition, provides a basis for design and type selecting of the fuses in the capacitor and effectively improves reliability of protection motions of the internal fuses and ensures that the temperature of the internal fuses will not damage internal insulation in the capacitor.