The kinetics of casein tryptic hydrolysis to prepare active peptides was investigated. Taking into account the reaction mechanism including single substrate hydrolysis, irreversible enzyme inactivation, and substrate inhibition, a set of exponential equations was established to characterize the enzymatic hydrolysis curves. The verification was carried out by a series of experimental results and indicated that the average regressive error was less than 5%. According to the proposed kinetic model, the kinetic constants and thermodynamic constants of the reaction system were also calculated. The kinetics of casein tryptic hydrolysis to prepare active peptides was investigated. Taking into account the reaction mechanism including single substrate hydrolysis, irreversible enzyme inactivation, and substrate inhibition, a set of exponential equations was established to characterize the enzymatic hydrolysis curves. out by a series of experimental results and indicated that the average regressive error was less than 5%. According to the proposed kinetic model, the kinetic constants and thermodynamic constants of the reaction system were also calculated.