An assay of desmosine (DES) in elastin hydrolysate was performed by HPLC. Desmosine alone or its mixture with tyrosine and phenylalanine as well as elastin hydrolysate was separated on a C18 column eluted with a mobile phase of MeOH:H2O (2:8, V/V) and detected at UV-280nm. The results showed that the time of DES eluted in all cases mentioned above was comparable. The ratio of peak area (CA) and peak height (CH) between DES and Tyr is 1.4% and 3.4% resectively. It could be as a reliable measure to evaluate the quantity of DES in elastin. The correlation coefficient r was 0.9956 in the range of 0.16-0.64mg/L for a calibration curve of DES concentration vs peak area. In conclusion, this method could be used as a biochemical indication to detect the degradation level of elastin in the pathological state.