In order to investigate the effects of Cl- and citrus flavonoids on pancreatic amylase activity and starch digestion in vitro， the effect of Cl- on the enzymatic properties of pancreatic amylase was studied by DNS method， and the effects of citrus flavonoids on pancreatic amylase activity and starch digestion were studied with or without Cl-， and the interaction mechanism of Cl- and citrus flavonoids with pancreatic amylase was studied by fluorescence spectrometry. The results showed that Cl- was an activator of pancreatic amylase， and the activation showed a dose-dependent effect. 10 mmol/L Cl- (equivalent to the salt intake of 4.5 g/d) could fully activate pancreatic amylase. Cl- could increase the optimum temperature(from 37 ℃ to 47 ℃) and thermal stability (inactivation temperature increased from 47 ℃ to 57 ℃)， and change the optimal pH (from 6 to 7) of pancreatic amylase without changing its pH stability. In the absence of Cl-， high concentration of flavonoids had inhibitory effect on pancreatic amylase， with the highest inhibition rate 17.1%， but 10 mmol/L Cl- could relieve the inhibition. 10 mmol/L Cl- could significantly increase the starch digestion rate， and citrus flavonoids of final mass concentration 0.056 mg/mL had no effect on starch digestion. The results of fluorescence spectrum experiment showed that the fluorescence of pancreatic amylase was statically quenched by binding citrus flavonoids， and 10 mmol/L Cl- had no effect on the fluorescence spectrum of pancreatic amylase interaction with citrus flavonoids. The results of this study can provide reference for starch digestion in vitro and the development of citrus flavonoid functional food.