Abstract: The inhibitory effect of kaempferol on α- amylase had been studied by enzymatic kinetics and fluorescence spectroscopy. Results indicated that kaempferol showed inhibition effect on the catalytic activity ofα-amylase. The type of inhibition effect was a noncompetitive ihibition. α-Amylase (0.328U/mL, 0.2mL) was treated by kaempferol (1mg/mL, 0.05mL) under pH6.8, 37℃ for 20min, the inhibition rate reached 24.39%. The regular quenching of intrinsic fluorescence of α-amylase could be induced by kaempferol as a quencher in physiological condition, and the quenching mechanism was a static quenching. Kaempferol could bind spontaneously with α-amylase to form a new complex by hydrophobic. There was only one binding constant between kaempferol and α-amylase.