Phosphatase is a key enzyme involved in the degradation of inosinic acid(IMP) in aquatic products. Acid phosphatase from sea bass(Lateolabrax japonicus) liver was used as the research object. Through homologous modeling， molecular docking and other means， ACP inhibitors were selected from traditional Chinese medicine compounds and their inhibition mechanism was studied. The results showed that benzoic acid， quercetin， hexadecanoic acid and dihydroresveratrol have strong inhibitory effect on phosphatase activity. The results showed that hydrogen bond and van der Waals force were the main driving forces for the combination of hexadecanoic acid and ACP， which results in the decrease of the fluorescence intensity， the red shift of the maximum emission wavelength of ACP. The combination of hexadecanoic acid with the active center of ACP changed the two-dimensional and three-dimensional structure of ACP， reduced the contact between ACP and inosinic acid (IMP)， and delays the degradation of IMP.