The effect of substituents on the UV absorption spectra of Diphenylfulvens was expressed by the substituents excited state parameter σexCC and ground state polarity parameter σp, and the obtained result was more accurate from the above two parameters than from the single parameter σ+p. The change rule of UV absorption spectrum of Diphenylfulvens in more than 10 kinds of different solvents was expressed by using three parameters, σexCC, σp and the solvatochromic dye ET(30), and the ET(30) was better than the n-octanol/water partition coefficient logP in scaling the solvent effect. Research shows that carbon disulfide may be an unsuitable solvent for determining the UV absorption spectrum of Diphenylfulvens.Key words: Diphenylfulvens; UV absorption spectra; substituents effect; solvents effect