In order to overcome the disadvantages of the purple ptoato pigment as sensitizer in dye sensitized solar cell,chemical modification is carried out by using caffeic acid as the acylati on agent.This article studies on the reaction time,temperature and raw material ratio on modification effect.Orthog onal experiment is carried out to find out the best experiment scheme,and the preparation of the acylated pigme nt under the optimum conditions is obtained for the performance test.The results show that when the temperature is 60℃,reaction time is 20min and material ratio is 0.1g/20mL,the ultraviol et spectrum absorption effect of acylated pigment is the best.The acylation enhance the absorption strength,adsorption capacity and stability of anthocyanin,and it also decreases the band gap.The dye-sensitized solar cell is fabricated by pigment and acylated pigment as sensitizers,and we can see that the photoelectric conversion efficie ncy is improved by 21%.