Abstract: The objective of this study was to investigate the effects of chlorogenic acid on the oxidation and N-nitrosodiethylamine(NDEA)formation of pork myofibrillar protein(MP)in hydroxyl radical oxidation system. Results showed that carbonyl content and thiol group was increased,the structure of protein was extended. Treatments with 0.1~0.5 mmol/L chlorogenic acid could significantly inhibit the increase of carbonyl content(p<0.05),but did not prevent carbonyl content formation at 0.8~1.0 mmol/L chlorogenic acid. Treatments with 0.1~2.0 mmol/L chlorogenic acid increased the hydrophobicity of MP and decreased the fluorescence intensity of tryptophan. Chlorogenic acid has a concentration dependent on the formation of NDEA. The NDEA generation was promoted by chlorogenic acid at 0.1~0.8 mmol/L,while it was inhibited by chlorogenic acid at 0.8~2.0 mmol/L. In conclusion:the appropriate amount of chlorogenic acid can inhibit the oxidation of myofibrillar proteins and NDEA formation.