A method for quantitation of collagen was established by detecting marker peptide with high performance liquid chromatography-mass spectrometry (HPLC-MS). Theoretical marker peptides were selected by sequence comparison. Bovine collagen type I was digested with trypsin. Marker peptides typical for collagen type I were identified with HPLC-MS. The relationship between the abundance of marker peptides and collagen concentration was established. The results show that GEAGPSGPAGPTGAR and the other 5 peptides showed high resolution during chromatographic separation and high signal intensity during MS analysis. Peptide signal intensity and collagen concentration showed a good linear relationship in the range from 0.1 to 3 mg/mL. Bovine tendon and collagen sponge were used as actual samples and collagen contents were determined as 90.2% and 93.4% respectively. Quantitation of marker peptides of collagen was a feasible method to identify and quantify collagens in medical device research and development.