Objective: To evaluate effect of the Carapax trionycis' total amino acids and oligo-peptide' content of the aqueous extract and alcohol extract on monoamine oxidase (MAO) activity. Method: C. trionycis aqueous extract and alcohol extract were prepared

then glutamic acid and C trionycis' oligo-peptide were used to establish standard material content respectively to calculate aqueous extract and alcohol extract total amino acid and oligo-peptide content

and observe the effect on MAO in vitro. Result: The extracted yield of the aqueous extract and alcohol extract was 20.6% and 5.4%

respectively;the oligo-peptide content of the aqueous extract and alcohol extract was (48.13±3.72)% and (20.17±2.49)% respectively;the total amino acid content of the aqueous extract and alcohol extract was (23.68±1.76)% and (55.88±2.41)% respectively;the aqueous extract and alcohol extract have inhibitory effect on MAO and the inhibition rate was (65.12±1.34)% and (50.95±1.13)% respectively. Conclusion: After the water was extracted

the extract yield is better than that of the alcohol extract;the aqueous extract and alcohol extract have inhibitory effect on MAO activity

and the effect of the aqueous extract is slightly stronger than that of the alcohol extract;the aqueous extract oligo-peptide content was higher than that of alcohol extract;alcohol extract total amino acid content is higher than that of the aqueous extract.It is better to extract the C using water

and water soluble constituents and alcohol soluble components in C have inhibitory activity on MAO and they are effective chemical constituents.