An ultra-broadband absorption spectral database encompassing 20 solid-state amino acids is meticulously constructed, spanning an unprecedented frequency range of 0.2-120 THz (6.7-4000 cm-1). Spectral acquisition is achieved through a hybrid methodology: terahertz time-domain spectroscopy (THz-TDS) is employed for the low-frequency regime (0.2-3 THz, 6.7-100 cm-1), while Fourier transform infrared spectroscopy (FTIR) is utilized to probe the far-infrared (FIR: 1.5-20.4 THz, 50-680 cm-1) and mid-infrared (MIR: 12-120 THz, 400-4000 cm-1) regions. These comprehensive measurements are systematically analyzed and cross-validated against previous data, thereby verifying and supplementing the amino acids spectral database. Furthermore, we propose a novel, user-friendly powder sample preparation approach for FIR spectroscopy, significantly enhancing operational efficiency, and accessibility-thereby lowering the barrier to adoption for researchers investigating low-frequency vibrational phenomena.