The fluorescence characteristics of the para-terphenyl vapour have been studied systematically. Its absorption, fluorescence and spectra have been measured. The fluorescence quantum yield is dependent on temperature, concentration and especially exciting wavelength. We explain the unusual fluorescence characteristics of organic scintillator represented by para-terphenyl in terms of "The effect of de-cage and inner-rotation". The first order of the Stoke s line of stimulated Raman scattering of KrF laser in hydrogen gas and the second order of the Stoke's line in methane have been used to pump para-terphonyl vapoux. No laser output was observed.