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The flavonoid derivatives of 4′-dimethylaminoflavonol (DMAF) in acetonitrile solvent and 3,7-dihydroxy-4-oxo-2-phenyl-4H-chromene-8-carbaldehyde (2a) in methylcyclohexane solvent have been investigated on the excited-state intramolecular proton transfer (ESIPT) based on the time-dependent density functional theory (TDDFT) method. The calculated absorption and fluorescence spectra agree well with the experimental results. The analyses of bond distance, bond angle, the molecular electrostatic potential surface and the infrared vibrational spectra show that intramolecular hydrogen bonds were formed in the S₀ state, and upon excitation, the intramolecular hydrogen bonds were strengthened in the S₁ state, which can facilitate the proton-transfer (PT) process. The constructed potential-energy curves/surfaces (PES) on the S₁ and S₀ states can be used to demonstrate the PT process. In terms of DMAF with one hydrogen bond, our calculations suggest that intramolecular hydrogen bonds can boost intramolecular PT in the twisted intramolecular charge-transfer (TICT) state. For the flavonoid derivative bearing two hydrogen bonds, i.e., 2a, however, the TICT state has little impact on 2a. Instead, three PT types in the excited state (ES) occur. By analyzing the PES, the preferred pathway was also determined. Our work not only gives a detailed PT process in the ES but also provides theoretical significance for further study of flavonoid derivatives.