Under simulated physiological conditions (pH=7.40), the interaction between non-steroidal anti-inflammatory drug mopicol and lipase was studied by fluorescence spectrum, ultraviolet absorption spectrum, circular dichroism spectrum and computer simulation technique. The experimental results showed that Mobic could quench the fluorescence of lipase by static quenching, and the binding site number is about 1. According to Förster's theory of non-radiation energy transfer, the binding distance between Mobic and lipase was obtained, r<7 nm, which indicated that there was non-radiation energy transfer in the system. The thermodynamic parameters were obtained from van't Hoff equation, Gibbs free energy ΔG<0, indicating that the reaction between them was spontaneous, ΔH<0, ΔS>0, indicating that hydrophobic force played a major role in the formation of Mobic and lipase complex. The results of synchronous fluorescence spectra, UV spectra and circular dichroism spectra showed that Mobic changed the conformation of lipase. The molecular docking results showed that the binding position of Mobic was close to the active center, indicating that Mobic could change the microenvironment of amino acid residues at the active center of lipase catalysis. The results of docking showed that there was hydrogen bond between Mobic and lipase, so the interaction between Mobic and lipase was driven by hydrophobic interaction and hydrogen bond.