The invention relates to the field of 
nuclear fusion and 
optical diagnosis and discloses a method for detecting instant temperature of a 
graphite tile of a partial filter of a 
magnetic confinement fusion device. The technical schemes includes that when the 
magnetic confinement fusion device works normally, terahertz 
waves are perpendicularly injected into the 
graphite tile from a position outside a window, and a probe is used for measuring and recording a terahertz time-domain spectrum 
Omega<T>(t) reflected by the 
graphite tile under 
working temperature. The time-domain spectrum is analyzed and processed and transformed in Fourier transformation in an 
effective frequency domain to obtain a 
frequency domain spectrum F<T>(
omega) under the 
working temperature. At the moment, data automatically selects a characteristic 
spectral line, reads positions of the characteristic 
spectral line in a data base under calibrated temperature, 
frequency shift amount is obtained by comparing the two positions, a 
functional relationship of 
frequency shift amount - temperature of the data base is compared with the 
frequency shift amount, and the instant temperature is then calculated, outputted and led to a computer 
system to be stored. According to the method for detecting the instant temperature of the graphite tile of the partial filter of the 
magnetic confinement fusion device, technology of reflecting the terahertz time-domain spectrum is adopted, the 
thermal shock instant temperature of the graphite tile of the partial filter of the magnetic confinement fusion device can be detected online, synchronously, and without contact or damage.