Abstract: To systematically study the laws and mechanisms of thiophene-based π-bridges regulating the photovoltaic performance of porphyrin dye sensitizers, the zinc porphyrin dye sensitizers were designed with thiophene, bithiophene, terthiophene, thieno3, 2-bthiophene and bithieno3, 2-b: 2', 3'-dthiophene as π-bridges. The properties of spectral absorption, intramolecular charge transfer, electron injection and dye regeneration of the porphyrin dye sensitizers were simulated and calculated using the density functional theory and time-dependent density functional theory methods. Results show that the difference of thiophene-based π-bridges mainly affects the intensity of the absorption spectra, and has negligible effect on the absorption spectral range of porphyrin dye sensitizers. Compared to porphyrin dye sensitizers with thiophene as π-bridge, bithiophene, terthiophene, thieno3, 2-bthiophene and bithieno3, 2-b: 2', 3'-dthiophene as π-bridges can enhance the absorption spectral intensity, which is conducive to the enhancement of the light harvesting efficiency of porphyrin dye sensitizers. However, their introduction also increases the degree of hole-electron overlap and reduces the dye regeneration ability, which results in the worse intramolecular charge transfer ability and dye regeneration ability. Terthiophene acting as π-bridge makes the porphyrin dye sensitizer have the highest light harvesting efficiency, but also the worst intramolecular charge transfer ability and dye regeneration ability.