In this paper, m-substituted benzaldehydes and home of Phosphonium as raw material by Witting reaction, synthesis of the 7 different substituents p-XC6H4CH = CHC6H4X-p, and their structures were determined by nuclear magnetic resonance, and measured the corresponding UV absorption spectrum. Quantitative changes in the single substituted p-XC6H4CH = CHC6H4X-p of the UV absorption spectra. Combined with the experimental data of other researchers to further explore the changes in the double substituted p-XC6H4CH = CHC6H4X-p of the ultraviolet spectrum law. The results show that the substituent parameters of the excited state of the system adapted to the UV spectra.还有关键词啊。。。继续，谢啦