Abstract: In this paper, the fluorescence characteristics of Polystytene(PS) in tetrahydrofuran and toluene were studied by fluorescence spectrometry and the effect of concentration on the fluorescence properties was also studied. The results showed that the emission wavelength of PS in tetrahydrofuran is 345 nm, with a saturation concentration of fluorescence intensity of 0.1 mg/mL, while the emission wavelength of PS in toluene is 310 nm, and the saturation concentration of fluorescence intensity is 0.75 mg/mL. The reason is: due to the intrinsic property of tetrahydrofuran interaction between tetrahydrofuran and PS do not exist. However, the benzene ring of toluene can strongly interact with the benzene ring of PS to form a T structure dimmer, as a result, the saturation concentration of PS in toluene is less than PS in tetrahydrofuran, and since the fluorescence frequencies of the PS and toluene chromophores are near, when the two groups are close enough, the intrinsic fluorescence emission wavelength of PS blueshifts from 340 nm to 310 nm through energy transfer. In addition, with the increase of the concentration of PS in the solution, the fluorescent intensity increases linearly at the beginning, and when the concentration is raised to higher that the saturation concentration C^*, then the fluorescent intensity decreases nonlinearly, this primarily is because PS dimers are formed in the solvent.