A rapid,sensitive and highly precise method was developed for the direct and continuous determination of the inhibitory effect on mushroom tyrosinase activity of natural products.Based on ο-quinone,L-DOPA was catalyzed by tyrosinase into the corresponding brown product,which has the biggest absorption at 475 nm.The tyrosinase inhibitor can reduce the enzymatic reaction rate,and then make the OD475 lower into a negative peak.The RSD of injection 10 times on the IC50 of kojic acid is 0.036%,and the precision of the approach was improved more than 10 times as compared with the spectrophotometric method and microtitration assay.By using the sample for further verification,the results showed that caffeic acid has a potent activating effect on diphenolase activities of tyrosinase,its concentration leading to 50% activation rate（IC50 ） is 0.170 mmol/L.The water-soluble extraction from Lavandula angustifolia has a potent inhibitory effect on diphenolase activities of tyrosinase,its IC50 value is 0.96 mg/mL.Compared with the spectrophotometric method and microtitration assay,flow injection-spectrophotometric approach has a higher precision,better repeatability and is suitable for the determination of influence on tyrosinase activity from natural products.