Abstract: Many kinds of nuclear reactor facilities had been successively developed and applied with the flourishing development of nuclear energy industry in our country. Knowledge of the information about the neutron spectra in-core of reactors is significant for their performance diagnoses and safe operations. According to fission and fusion reactors, the suitable measuring methods of the neutron spectra and the developed neutron spectrometers in the near several decades were expatiated so as to provide some references for the related researches in the future.