Abstract: The protein changes of Xuanen ham from raw leg to finished product in the entire processing stage were analyzed,the results showed that the content of non-protein nitrogen increased from 685.9 mg/100 g to 1724.3 mg/100 g in the raw material leg in the finished product. The polypeptide nitrogen in non-protein nitrogen continued to rise throughout the processing stage,and the increase in the end of fermentation was greater. The amino acid nitrogen content increased rapidly in the early stage of fermentation,and decreased slightly at the end stage. The change of volatile base nitrogen content was consistent with amino acid nitrogen. The content of taste amino acids increased significantly during the whole process,from 315.8 mg/100 g to 2171.3 mg/100 g,and the glutamic acid content increased by 29.6 times. Among the proteins of Xuanen ham,the content of sarcoplasmic protein and myofibrillar protein decreased due to degradation,especially in the middle and late stages of fermentation,and the sarcoplasmic protein was more thoroughly degraded than myofibrillar protein. The meat matrix protein content increased at the beginning of the fermentation due to thermal denaturation of the protein and then remained stable. All in all,the hydrolysis of protein was accompanied by the processing of the entire Xuanen ham,especially in the middle and late stages of fermentation,the degree of hydrolysis was more obvious,which played an important role in the formation of the unique flavor of ham.