The invention discloses a research method of low-frequency vibration of an indomethacin-nicotinamide co-crystal. The research method of low-frequency vibration of the indomethacin-nicotinamide co-crystal comprises the following steps: firstly, performing spectral analysis on the indomethacin-nicotinamide co-crystal by using the terahertz time-domain spectroscopy; then using the planar wave-based solid density functional software VASP to optimize the crystal structure, and using the Phonopy-spectroscopy program to calculate the infrared absorption spectrum of the sample; and performing contrastive analysis on the calculated spectrum and the experimental spectrum, and performing vibration analysis on the absorption peaks in the calculated spectrum, so as to obtain the research results of thelow-frequency vibration characteristics of the indomethacin-nicotinamide co-crystal. The research method of low-frequency vibration of the indomethacin-nicotinamide co-crystal promotes the development of indomethacin-nicotinamide drug co-crystal and has far-reaching significance.