The complex fingerprint and quantitative analysis of ten licorice flavonoids revealed the binding activity of the flavonoids with NOS2 in liver cancer, indicating that LCA, LCB, LCC, LCD, LCE, LCF, LCG, Glypallichalcone, Echinatin, and 3,4,3′,4′Tetrahydroxy-2-methoxychalcone can interact with specific proteins in liver cancer patients through key amino acid residues. The gene discussed is NOS2; the disease is liver cancer.