Abstract: Based on the experimental research of the UV-light absorption spectra and the fluorescent spectra of methanol,the spectral characteristics and the physical mechanisms were investigated.The research outcomes indicate that methanol molecules can absorb the exciting light with a maximum wavelength of 260nm and they can emit fluorescence with a peak value of 340nm.And by means of the concentration change,fluorescent intensity had a regular change.Meanwhile the absorbing-emitting mechanism of methanol molecule was also discussed.The results of this research will give the theoretical support to measurement mini-quantity and reference to diagnose technique of methanol molecules.