The dynamic interaction process of calmodulin with an immobilized peptide melittin was investigated in real time by surface plasmon resonance spectroscopy, and dissociation constant of the complex was calculated to be 3.3710-6 mol/L. The dynamic interaction process of calmodulin with an immobilized peptide melittin was investigated in real time by surface plasmon resonance spectroscopy, and dissociation constant of the complex was calculated to be 3.3710-6 mol / L.