Abstract: In the study,Jiaosu of Cudrania tricuspidata the fruit,flower and leave were made respectively,according to the traditional fermentation process of plant Jiaosu. The amino acid type,content and antioxidant activity were studied. The results showed that the three kinds of Jiaosu were rich in amino acids,total amino acids were 12.667,2.870,1.198 mg/mL respectively. The ratio of essential amino acids to total amino acids were 32.8%,32.9% and 40.0% respectively,and the ratio coefficients were 54.31,31.65 and 46.49,the Jiaosu of Cudrania tricuspidata fruit had higher nutritional value. The main amino acids of the three kinds of Jiaosu were aspartic acid,serine,glutamic acid,glycine,alanine,valine,isoleucine,leucine and lysine sour,cysteine and methionine content were minimal. Antioxidant capacity of the three Jiaosu were very strong,of which the Jiaosu of Cudrania tricuspidata fruit had better antioxidant activity than that of Jiaosu of Cudrania tricuspidata flower and leave,and ABTS free radical scavenging ability,DPPH free radical scavenging ability,hydroxyl radical scavenging ability and reducing power all showed concentration dependency. There was a positive correlation between amino acid content and antioxidant activity,especially Asp,Glu,Ala,His,Arg and Pro which had a significant positive correlations with reducing power(r>0.99). The reducing power could be used to evaluate the antioxidant properties of Cudrania tricuspidata Jiaosu.